20513915 has 16 divisors (see below), whose sum is σ = 25272000. Its totient is φ = 15979392.

The previous prime is 20513903. The next prime is 20513921. The reversal of 20513915 is 51931502.

It is a cyclic number.

It is not a de Polignac number, because 20513915 - 2⁸ = 20513659 is a prime.

It is an unprimeable number.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 52541 + ... + 52929.

It is an arithmetic number, because the mean of its divisors is an integer number (1579500).

Almost surely, 2^20513915 is an apocalyptic number.

20513915 is a deficient number, since it is larger than the sum of its proper divisors (4758085).

20513915 is a wasteful number, since it uses less digits than its factorization.

20513915 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 646.

The product of its (nonzero) digits is 1350, while the sum is 26.

The square root of 20513915 is about 4529.2289630797. The cubic root of 20513915 is about 273.7470937884.

The spelling of 20513915 in words is "twenty million, five hundred thirteen thousand, nine hundred fifteen".