20720872 has 16 divisors (see below), whose sum is σ = 38901060. Its totient is φ = 10347264.

The previous prime is 20720789. The next prime is 20720893. The reversal of 20720872 is 27802702.

It can be written as a sum of positive squares in 2 ways, for example, as 20666116 + 54756 = 4546^2 + 234^2 .

It is a self number, because there is not a number n which added to its sum of digits gives 20720872.

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, 9378 + ... + 11374.

Almost surely, 2^20720872 is an apocalyptic number.

It is an amenable number.

20720872 is a deficient number, since it is larger than the sum of its proper divisors (18180188).

20720872 is a wasteful number, since it uses less digits than its factorization.

20720872 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 3300 (or 3296 counting only the distinct ones).

The product of its (nonzero) digits is 3136, while the sum is 28.

The square root of 20720872 is about 4552.0184533897. The cubic root of 20720872 is about 274.6645916308.

The spelling of 20720872 in words is "twenty million, seven hundred twenty thousand, eight hundred seventy-two".