21556056 has 32 divisors (see below), whose sum is σ = 54014400. Its totient is φ = 7168800.

The previous prime is 21556027. The next prime is 21556057. The reversal of 21556056 is 65065512.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21556057) 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, 14131 + ... + 15581.

It is an arithmetic number, because the mean of its divisors is an integer number (1687950).

Almost surely, 2^21556056 is an apocalyptic number.

It is an amenable number.

21556056 is an abundant number, since it is smaller than the sum of its proper divisors (32458344).

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

21556056 is a wasteful number, since it uses less digits than its factorization.

21556056 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 2079 (or 2075 counting only the distinct ones).

The product of its (nonzero) digits is 9000, while the sum is 30.

The square root of 21556056 is about 4642.8499868077. The cubic root of 21556056 is about 278.3063407037.

The spelling of 21556056 in words is "twenty-one million, five hundred fifty-six thousand, fifty-six".