21900928 has 32 divisors (see below), whose sum is σ = 49865760. Its totient is φ = 9385728.

The previous prime is 21900883. The next prime is 21900937. The reversal of 21900928 is 82900912.

It is a tau number, because it is divible by the number of its divisors (32).

It is a super-2 number, since 2×21900928² = 959301294522368, which contains 22 as substring.

It is a self number, because there is not a number n which added to its sum of digits gives 21900928.

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, 11326 + ... + 13117.

It is an arithmetic number, because the mean of its divisors is an integer number (1558305).

Almost surely, 2^21900928 is an apocalyptic number.

21900928 is a gapful number since it is divisible by the number (28) formed by its first and last digit.

It is an amenable number.

21900928 is an abundant number, since it is smaller than the sum of its proper divisors (27964832).

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

21900928 is an equidigital number, since it uses as much as digits as its factorization.

21900928 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 24464 (or 24452 counting only the distinct ones).

The product of its (nonzero) digits is 2592, while the sum is 31.

The square root of 21900928 is about 4679.8427324003. The cubic root of 21900928 is about 279.7826885284.

The spelling of 21900928 in words is "twenty-one million, nine hundred thousand, nine hundred twenty-eight".