21953856 has 28 divisors (see below), whose sum is σ = 58086752. Its totient is φ = 7317888.

The previous prime is 21953849. The next prime is 21953861. The reversal of 21953856 is 65835912.

It is a congruent number.

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 56980 + ... + 57363.

Almost surely, 2^21953856 is an apocalyptic number.

It is an amenable number.

21953856 is an abundant number, since it is smaller than the sum of its proper divisors (36132896).

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

21953856 is a wasteful number, since it uses less digits than its factorization.

21953856 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 114358 (or 114348 counting only the distinct ones).

The product of its digits is 64800, while the sum is 39.

The square root of 21953856 is about 4685.4942108597. The cubic root of 21953856 is about 280.0078909341.

The spelling of 21953856 in words is "twenty-one million, nine hundred fifty-three thousand, eight hundred fifty-six".