21970928 has 20 divisors (see below), whose sum is σ = 48650160. Its totient is φ = 9416064.

The previous prime is 21970913. The next prime is 21970931. The reversal of 21970928 is 82907912.

It is a junction number, because it is equal to n+sod(n) for n = 21970891 and 21970900.

It is a congruent number.

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, 97973 + ... + 98196.

It is an arithmetic number, because the mean of its divisors is an integer number (2432508).

Almost surely, 2^21970928 is an apocalyptic number.

21970928 is a gapful number since it is divisible by the number (28) formed by its first and last digit.

It is an amenable number.

21970928 is an abundant number, since it is smaller than the sum of its proper divisors (26679232).

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

21970928 is a wasteful number, since it uses less digits than its factorization.

21970928 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 196184 (or 196178 counting only the distinct ones).

The product of its (nonzero) digits is 18144, while the sum is 38.

The square root of 21970928 is about 4687.3156497083. The cubic root of 21970928 is about 280.0804530715.

The spelling of 21970928 in words is "twenty-one million, nine hundred seventy thousand, nine hundred twenty-eight".