21357532 has 18 divisors (see below), whose sum is σ = 43478232. Its totient is φ = 9153144.

The previous prime is 21357529. The next prime is 21357563. The reversal of 21357532 is 23575312.

It is a super-2 number, since 2×21357532² = 912288346262048, which contains 22 as substring.

It is a Harshad number since it is a multiple of its sum of digits (28).

It is a self number, because there is not a number n which added to its sum of digits gives 21357532.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 5 ways as a sum of consecutive naturals, for example, 54288 + ... + 54679.

Almost surely, 2^21357532 is an apocalyptic number.

It is an amenable number.

21357532 is an abundant number, since it is smaller than the sum of its proper divisors (22120700).

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

21357532 is a wasteful number, since it uses less digits than its factorization.

21357532 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 108985 (or 108976 counting only the distinct ones).

The product of its digits is 6300, while the sum is 28.

The square root of 21357532 is about 4621.4209935906. The cubic root of 21357532 is about 277.4493352300.

The spelling of 21357532 in words is "twenty-one million, three hundred fifty-seven thousand, five hundred thirty-two".