21957008 has 20 divisors (see below), whose sum is σ = 44781360. Its totient is φ = 10400544.

The previous prime is 21956983. The next prime is 21957043. The reversal of 21957008 is 80075912.

It is a super-2 number, since 2×21957008² = 964220400624128, which contains 22 as substring.

It is a hoax number, since the sum of its digits (32) coincides with the sum of the digits of its distinct prime factors.

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, 35810 + ... + 36417.

It is an arithmetic number, because the mean of its divisors is an integer number (2239068).

Almost surely, 2^21957008 is an apocalyptic number.

It is an amenable number.

21957008 is an abundant number, since it is smaller than the sum of its proper divisors (22824352).

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

21957008 is a wasteful number, since it uses less digits than its factorization.

21957008 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 72254 (or 72248 counting only the distinct ones).

The product of its (nonzero) digits is 5040, while the sum is 32.

The square root of 21957008 is about 4685.8305560487. The cubic root of 21957008 is about 280.0212908980.

The spelling of 21957008 in words is "twenty-one million, nine hundred fifty-seven thousand, eight".