21534556 has 12 divisors (see below), whose sum is σ = 37723168. Its totient is φ = 10756512.

The previous prime is 21534551. The next prime is 21534577. The reversal of 21534556 is 65543512.

It is a hoax number, since the sum of its digits (31) coincides with the sum of the digits of its distinct prime factors.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21534551) 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, 3280 + ... + 7336.

Almost surely, 2^21534556 is an apocalyptic number.

It is an amenable number.

21534556 is a deficient number, since it is larger than the sum of its proper divisors (16188612).

21534556 is a wasteful number, since it uses less digits than its factorization.

21534556 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 5388 (or 5386 counting only the distinct ones).

The product of its digits is 18000, while the sum is 31.

The square root of 21534556 is about 4640.5340209937. The cubic root of 21534556 is about 278.2137823871.

The spelling of 21534556 in words is "twenty-one million, five hundred thirty-four thousand, five hundred fifty-six".