21634956 has 36 divisors (see below), whose sum is σ = 62501712. Its totient is φ = 6181344.

The previous prime is 21634919. The next prime is 21634961. The reversal of 21634956 is 65943612.

It is a happy number.

21634956 is a `hidden beast` number, since 2 + 163 + 495 + 6 = 666.

It is a tau number, because it is divible by the number of its divisors (36).

It is a super-2 number, since 2×21634956² = 936142642243872, which contains 22 as substring.

It is a Harshad number since it is a multiple of its sum of digits (36).

It is a self number, because there is not a number n which added to its sum of digits gives 21634956.

It is an unprimeable number.

It is a polite number, since it can be written in 11 ways as a sum of consecutive naturals, for example, 42675 + ... + 43178.

Almost surely, 2^21634956 is an apocalyptic number.

It is an amenable number.

21634956 is an abundant number, since it is smaller than the sum of its proper divisors (40866756).

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

21634956 is a wasteful number, since it uses less digits than its factorization.

21634956 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 85870 (or 85865 counting only the distinct ones).

The product of its digits is 38880, while the sum is 36.

The square root of 21634956 is about 4651.3391620049. The cubic root of 21634956 is about 278.6454818059.

The spelling of 21634956 in words is "twenty-one million, six hundred thirty-four thousand, nine hundred fifty-six".