21934656 has 84 divisors (see below), whose sum is σ = 63616332. Its totient is φ = 7225344.

The previous prime is 21934613. The next prime is 21934667. The reversal of 21934656 is 65643912.

It is a happy number.

21934656 is a `hidden beast` number, since 2 + 193 + 465 + 6 = 666.

It can be written as a sum of positive squares in 2 ways, for example, as 2433600 + 19501056 = 1560^2 + 4416^2 .

It is a super-2 number, since 2×21934656² = 962258267676672, which contains 22 as substring.

It is a Smith number, since the sum of its digits (36) coincides with the sum of the digits of its prime factors.

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 21934656.

It is a congruent number.

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, 64920 + ... + 65256.

Almost surely, 2^21934656 is an apocalyptic number.

It is an amenable number.

It is a practical number, because each smaller number is the sum of distinct divisors of 21934656, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (31808166).

21934656 is an abundant number, since it is smaller than the sum of its proper divisors (41681676).

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

21934656 is a wasteful number, since it uses less digits than its factorization.

21934656 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 468 (or 455 counting only the distinct ones).

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

The square root of 21934656 is about 4683.4448859787. Note that the first 3 decimals coincide. The cubic root of 21934656 is about 279.9262390741.

The spelling of 21934656 in words is "twenty-one million, nine hundred thirty-four thousand, six hundred fifty-six".