21670928 has 20 divisors (see below), whose sum is σ = 42072828. Its totient is φ = 10813440.

The previous prime is 21670897. The next prime is 21670933. The reversal of 21670928 is 82907612.

It is a happy number.

It can be written as a sum of positive squares in 2 ways, for example, as 7772944 + 13897984 = 2788^2 + 3728^2 .

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, 9200 + ... + 11312.

Almost surely, 2^21670928 is an apocalyptic number.

It is an amenable number.

21670928 is a deficient number, since it is larger than the sum of its proper divisors (20401900).

21670928 is a wasteful number, since it uses less digits than its factorization.

21670928 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 2762 (or 2756 counting only the distinct ones).

The product of its (nonzero) digits is 12096, while the sum is 35.

The square root of 21670928 is about 4655.2043993793. The cubic root of 21670928 is about 278.7998290136.

The spelling of 21670928 in words is "twenty-one million, six hundred seventy thousand, nine hundred twenty-eight".