20709928 has 16 divisors (see below), whose sum is σ = 38882880. Its totient is φ = 10341168.

The previous prime is 20709917. The next prime is 20709937. The reversal of 20709928 is 82990702.

It is a super-2 number, since 2×20709928² = 857802235530368, which contains 22 as substring.

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, 7651 + ... + 9997.

It is an arithmetic number, because the mean of its divisors is an integer number (2430180).

Almost surely, 2^20709928 is an apocalyptic number.

It is an amenable number.

20709928 is a deficient number, since it is larger than the sum of its proper divisors (18172952).

20709928 is a wasteful number, since it uses less digits than its factorization.

20709928 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 3456 (or 3452 counting only the distinct ones).

The product of its (nonzero) digits is 18144, while the sum is 37.

The square root of 20709928 is about 4550.8161905311. The cubic root of 20709928 is about 274.6162272143.

The spelling of 20709928 in words is "twenty million, seven hundred nine thousand, nine hundred twenty-eight".