21056080 has 20 divisors (see below), whose sum is σ = 48955572. Its totient is φ = 8422400.

The previous prime is 21056069. The next prime is 21056089. The reversal of 21056080 is 8065012.

It is a happy number.

It can be written as a sum of positive squares in 2 ways, for example, as 3717184 + 17338896 = 1928^2 + 4164^2 .

It is a tau number, because it is divible by the number of its divisors (20).

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21056089) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 131521 + ... + 131680.

Almost surely, 2^21056080 is an apocalyptic number.

21056080 is a gapful number since it is divisible by the number (20) formed by its first and last digit.

It is an amenable number.

21056080 is an abundant number, since it is smaller than the sum of its proper divisors (27899492).

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

21056080 is a wasteful number, since it uses less digits than its factorization.

21056080 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 263214 (or 263208 counting only the distinct ones).

The product of its (nonzero) digits is 480, while the sum is 22.

The square root of 21056080 is about 4588.6904449963. The cubic root of 21056080 is about 276.1377873937.

The spelling of 21056080 in words is "twenty-one million, fifty-six thousand, eighty".