21862656 has 72 divisors (see below), whose sum is σ = 64672160. Its totient is φ = 7285248.

The previous prime is 21862651. The next prime is 21862667. The reversal of 21862656 is 65626812.

21862656 is a `hidden beast` number, since 21 + 8 + 626 + 5 + 6 = 666.

It is a tau number, because it is divible by the number of its divisors (72).

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 21862656.

It is not an unprimeable number, because it can be changed into a prime (21862651) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 5331 + ... + 8493.

Almost surely, 2^21862656 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 21862656, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (32336080).

21862656 is an abundant number, since it is smaller than the sum of its proper divisors (42809504).

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

21862656 is an equidigital number, since it uses as much as digits as its factorization.

21862656 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 3188 (or 3168 counting only the distinct ones).

The product of its digits is 34560, while the sum is 36.

The square root of 21862656 is about 4675.7519181411. The cubic root of 21862656 is about 279.6196195409.

The spelling of 21862656 in words is "twenty-one million, eight hundred sixty-two thousand, six hundred fifty-six".