21264056 has 32 divisors (see below), whose sum is σ = 43876080. Its totient is φ = 9660640.

The previous prime is 21264053. The next prime is 21264071. The reversal of 21264056 is 65046212.

It is a super-2 number, since 2×21264056² = 904320155142272, which contains 22 as substring.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21264053) 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, 9650 + ... + 11646.

Almost surely, 2^21264056 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 21264056, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (21938040).

21264056 is an abundant number, since it is smaller than the sum of its proper divisors (22612024).

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

21264056 is a wasteful number, since it uses less digits than its factorization.

21264056 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 2036 (or 2010 counting only the distinct ones).

The product of its (nonzero) digits is 2880, while the sum is 26.

The square root of 21264056 is about 4611.2965638744. The cubic root of 21264056 is about 277.0439703079.

The spelling of 21264056 in words is "twenty-one million, two hundred sixty-four thousand, fifty-six".