21064056 has 64 divisors (see below), whose sum is σ = 57177120. Its totient is φ = 6428160.

The previous prime is 21064051. The next prime is 21064073. The reversal of 21064056 is 65046012.

It is a super-2 number, since 2×21064056² = 887388910342272, which contains 22 as substring.

It is a Harshad number since it is a multiple of its sum of digits (24).

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21064051) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 56286 + ... + 56658.

Almost surely, 2^21064056 is an apocalyptic number.

21064056 is a gapful number since it is divisible by the number (26) formed by its first and last digit.

It is an amenable number.

It is a practical number, because each smaller number is the sum of distinct divisors of 21064056, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (28588560).

21064056 is an abundant number, since it is smaller than the sum of its proper divisors (36113064).

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

21064056 is a wasteful number, since it uses less digits than its factorization.

21064056 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 576 (or 572 counting only the distinct ones).

The product of its (nonzero) digits is 1440, while the sum is 24.

The square root of 21064056 is about 4589.5594559827. The cubic root of 21064056 is about 276.1726498016.

The spelling of 21064056 in words is "twenty-one million, sixty-four thousand, fifty-six".