21157252 has 24 divisors (see below), whose sum is σ = 38635520. Its totient is φ = 10126080.

The previous prime is 21157249. The next prime is 21157267. The reversal of 21157252 is 25275112.

It is an unprimeable number.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 11149 + ... + 12907.

Almost surely, 2^21157252 is an apocalyptic number.

It is an amenable number.

21157252 is a deficient number, since it is larger than the sum of its proper divisors (17478268).

21157252 is a wasteful number, since it uses less digits than its factorization.

21157252 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1891 (or 1889 counting only the distinct ones).

The product of its digits is 1400, while the sum is 25.

The square root of 21157252 is about 4599.7012946495. The cubic root of 21157252 is about 276.5793508432.

The spelling of 21157252 in words is "twenty-one million, one hundred fifty-seven thousand, two hundred fifty-two".