15 (fifteen) is the natural number following 14 and preceding 16.
20 (twenty) is the natural number following 19 and preceding 21.
21 (twenty-one) is the natural number following 20 and preceding 22.
33 (thirty-three) is the natural number following 32 and preceding 34.
In mathematics, a semiprime is a natural number that is the product of exactly two prime numbers. The two primes in the product may equal each other, so the semiprimes include the squares of prime numbers. Because there are infinitely many prime numbers, there are also infinitely many semiprimes. Semiprimes are also called biprimes, since they include two primes, or second numbers, by analogy with how "prime" means "first".
29 (twenty-nine) is the natural number following 28 and preceding 30. It is a prime number.
35 (thirty-five) is the natural number following 34 and preceding 36
89 (eighty-nine) is the natural number following 88 and preceding 90.
34 (thirty-four) is the natural number following 33 and preceding 35.
39 (thirty-nine) is the natural number following 38 and preceding 40.
46 (forty-six) is the natural number following 45 and preceding 47.
58 (fifty-eight) is the natural number following 57 and preceding 59.
65 (sixty-five) is the natural number following 64 and preceding 66.
91 (ninety-one) is the natural number following 90 and preceding 92.
120 is the natural number following 119 and preceding 121. It is five sixths of a gross, or ten dozens.
119 is the natural number following 118 and preceding 120.
1000 or one thousand is the natural number following 999 and preceding 1001. In most English-speaking countries, it can be written with or without a comma or sometimes a period separating the thousands digit: 1,000.
100,000 (one hundred thousand) is the natural number following 99,999 and preceding 100,001. In scientific notation, it is written as 105.
177 is the natural number following 176 and preceding 178.
254 is the natural number following 253 and preceding 255.
