21955968 has 64 divisors (see below), whose sum is σ = 64810800. Its totient is φ = 7317504.

The previous prime is 21955957. The next prime is 21955981. The reversal of 21955968 is 86955912.

It is a tau number, because it is divible by the number of its divisors (64).

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 280 + ... + 6632.

Almost surely, 2^21955968 is an apocalyptic number.

It is an amenable number.

It is a practical number, because each smaller number is the sum of distinct divisors of 21955968, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (32405400).

21955968 is an abundant number, since it is smaller than the sum of its proper divisors (42854832).

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

21955968 is an equidigital number, since it uses as much as digits as its factorization.

21955968 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 6376 (or 6358 counting only the distinct ones).

The product of its digits is 194400, while the sum is 45.

The square root of 21955968 is about 4685.7195818785. The cubic root of 21955968 is about 280.0168697319.

The spelling of 21955968 in words is "twenty-one million, nine hundred fifty-five thousand, nine hundred sixty-eight".