20513728 has 28 divisors (see below), whose sum is σ = 40901112. Its totient is φ = 10208000.

The previous prime is 20513687. The next prime is 20513729. The reversal of 20513728 is 82731502.

It is a junction number, because it is equal to n+sod(n) for n = 20513696 and 20513705.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (20513729) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 15426 + ... + 16702.

It is an arithmetic number, because the mean of its divisors is an integer number (1460754).

Almost surely, 2^20513728 is an apocalyptic number.

It is an amenable number.

20513728 is a deficient number, since it is larger than the sum of its proper divisors (20387384).

20513728 is a wasteful number, since it uses less digits than its factorization.

20513728 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1540 (or 1530 counting only the distinct ones).

The product of its (nonzero) digits is 3360, while the sum is 28.

The square root of 20513728 is about 4529.2083193424. The cubic root of 20513728 is about 273.7462619813.

The spelling of 20513728 in words is "twenty million, five hundred thirteen thousand, seven hundred twenty-eight".