21597132 has 12 divisors (see below), whose sum is σ = 50393336. Its totient is φ = 7199040.

The previous prime is 21597131. The next prime is 21597179. The reversal of 21597132 is 23179512.

It is a tau number, because it is divible by the number of its divisors (12).

It is a super-2 number, since 2×21597132² = 932872221250848, which contains 22 as substring.

It is a self number, because there is not a number n which added to its sum of digits gives 21597132.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21597131) 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, 899869 + ... + 899892.

Almost surely, 2^21597132 is an apocalyptic number.

It is an amenable number.

21597132 is an abundant number, since it is smaller than the sum of its proper divisors (28796204).

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

21597132 is a wasteful number, since it uses less digits than its factorization.

21597132 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1799768 (or 1799766 counting only the distinct ones).

The product of its digits is 3780, while the sum is 30.

The square root of 21597132 is about 4647.2714575329. The cubic root of 21597132 is about 278.4830034742.

The spelling of 21597132 in words is "twenty-one million, five hundred ninety-seven thousand, one hundred thirty-two".