21657152 has 28 divisors (see below), whose sum is σ = 46884336. Its totient is φ = 9843840.

The previous prime is 21657151. The next prime is 21657157. The reversal of 21657152 is 25175612.

It is a super-2 number, since 2×21657152² = 938064465502208, which contains 22 as substring.

It is not an unprimeable number, because it can be changed into a prime (21657151) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 14678 + ... + 16085.

Almost surely, 2^21657152 is an apocalyptic number.

21657152 is a gapful number since it is divisible by the number (22) formed by its first and last digit.

It is an amenable number.

21657152 is an abundant number, since it is smaller than the sum of its proper divisors (25227184).

It is a pseudoperfect number, because it is the sum of a subset of its proper divisors.

21657152 is a wasteful number, since it uses less digits than its factorization.

21657152 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 30786 (or 30776 counting only the distinct ones).

The product of its digits is 4200, while the sum is 29.

The square root of 21657152 is about 4653.7245298793. The cubic root of 21657152 is about 278.7407397032.

The spelling of 21657152 in words is "twenty-one million, six hundred fifty-seven thousand, one hundred fifty-two".