21997056 has 40 divisors (see below), whose sum is σ = 58605624. Its totient is φ = 7331840.

The previous prime is 21997043. The next prime is 21997061. The reversal of 21997056 is 65079912.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 5625 + ... + 8696.

Almost surely, 2^21997056 is an apocalyptic number.

It is an amenable number.

21997056 is an abundant number, since it is smaller than the sum of its proper divisors (36608568).

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

21997056 is an equidigital number, since it uses as much as digits as its factorization.

21997056 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 14342 (or 14326 counting only the distinct ones).

The product of its (nonzero) digits is 34020, while the sum is 39.

The square root of 21997056 is about 4690.1019178692. The cubic root of 21997056 is about 280.1914337144.

The spelling of 21997056 in words is "twenty-one million, nine hundred ninety-seven thousand, fifty-six".