21890928 has 20 divisors (see below), whose sum is σ = 56551688. Its totient is φ = 7296960.

The previous prime is 21890927. The next prime is 21890959. The reversal of 21890928 is 82909812.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21890927) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 227983 + ... + 228078.

Almost surely, 2^21890928 is an apocalyptic number.

It is an amenable number.

21890928 is an abundant number, since it is smaller than the sum of its proper divisors (34660760).

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

21890928 is a wasteful number, since it uses less digits than its factorization.

21890928 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 456072 (or 456066 counting only the distinct ones).

The product of its (nonzero) digits is 20736, while the sum is 39.

The square root of 21890928 is about 4678.7741984413. The cubic root of 21890928 is about 279.7400989659.

The spelling of 21890928 in words is "twenty-one million, eight hundred ninety thousand, nine hundred twenty-eight".