21056976 has 80 divisors (see below), whose sum is σ = 61305600. Its totient is φ = 6918912.

The previous prime is 21056963. The next prime is 21056993. The reversal of 21056976 is 67965012.

21056976 is a `hidden beast` number, since 21 + 0 + 569 + 76 = 666.

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 21056976.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 33820 + ... + 34436.

It is an arithmetic number, because the mean of its divisors is an integer number (766320).

Almost surely, 2^21056976 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 21056976, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (30652800).

21056976 is an abundant number, since it is smaller than the sum of its proper divisors (40248624).

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

21056976 is a wasteful number, since it uses less digits than its factorization.

21056976 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 713 (or 701 counting only the distinct ones).

The product of its (nonzero) digits is 22680, while the sum is 36.

The square root of 21056976 is about 4588.7880752983. The cubic root of 21056976 is about 276.1417041713.

The spelling of 21056976 in words is "twenty-one million, fifty-six thousand, nine hundred seventy-six".