21537072 has 30 divisors (see below), whose sum is σ = 60274292. Its totient is φ = 7178976.

The previous prime is 21537049. The next prime is 21537073. The reversal of 21537072 is 27073512.

It is not an unprimeable number, because it can be changed into a prime (21537073) by changing a digit.

It is a polite number, since it can be written in 5 ways as a sum of consecutive naturals, for example, 74638 + ... + 74925.

Almost surely, 2^21537072 is an apocalyptic number.

It is an amenable number.

21537072 is an abundant number, since it is smaller than the sum of its proper divisors (38737220).

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

21537072 is a wasteful number, since it uses less digits than its factorization.

21537072 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 149577 (or 149568 counting only the distinct ones).

The product of its (nonzero) digits is 2940, while the sum is 27.

The square root of 21537072 is about 4640.8051025657. The cubic root of 21537072 is about 278.2246170446.

The spelling of 21537072 in words is "twenty-one million, five hundred thirty-seven thousand, seventy-two".