21956080 has 20 divisors (see below), whose sum is σ = 51048072. Its totient is φ = 8782400.

The previous prime is 21956069. The next prime is 21956089. The reversal of 21956080 is 8065912.

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 (21956089) 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, 137146 + ... + 137305.

Almost surely, 2^21956080 is an apocalyptic number.

21956080 is a gapful number since it is divisible by the number (20) formed by its first and last digit.

It is an amenable number.

21956080 is an abundant number, since it is smaller than the sum of its proper divisors (29091992).

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

21956080 is a wasteful number, since it uses less digits than its factorization.

21956080 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 274464 (or 274458 counting only the distinct ones).

The product of its (nonzero) digits is 4320, while the sum is 31.

The square root of 21956080 is about 4685.7315330693. The cubic root of 21956080 is about 280.0173458642.

The spelling of 21956080 in words is "twenty-one million, nine hundred fifty-six thousand, eighty".