20215656 has 48 divisors (see below), whose sum is σ = 56784000. Its totient is φ = 6737904.

The previous prime is 20215621. The next prime is 20215661. The reversal of 20215656 is 65651202.

20215656 is a `hidden beast` number, since 2 + 0 + 2 + 1 + 5 + 656 = 666.

It is a hoax number, since the sum of its digits (27) coincides with the sum of the digits of its distinct prime factors.

It is a Harshad number since it is a multiple of its sum of digits (27).

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 11 ways as a sum of consecutive naturals, for example, 3256 + ... + 7143.

It is an arithmetic number, because the mean of its divisors is an integer number (1183000).

Almost surely, 2^20215656 is an apocalyptic number.

It is an amenable number.

20215656 is an abundant number, since it is smaller than the sum of its proper divisors (36568344).

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

20215656 is a wasteful number, since it uses less digits than its factorization.

20215656 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 10420 (or 10404 counting only the distinct ones).

The product of its (nonzero) digits is 3600, while the sum is 27.

The square root of 20215656 is about 4496.1823806425. The cubic root of 20215656 is about 272.4139099031.

Adding to 20215656 its reverse (65651202), we get a palindrome (85866858).

The spelling of 20215656 in words is "twenty million, two hundred fifteen thousand, six hundred fifty-six".