20518564 has 12 divisors (see below), whose sum is σ = 39171888. Its totient is φ = 9326600.

The previous prime is 20518529. The next prime is 20518577. The reversal of 20518564 is 46581502.

It is a super-2 number, since 2×20518564² = 842022937244192, which contains 22 as substring.

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 233122 + ... + 233209.

It is an arithmetic number, because the mean of its divisors is an integer number (3264324).

Almost surely, 2^20518564 is an apocalyptic number.

It is an amenable number.

20518564 is a deficient number, since it is larger than the sum of its proper divisors (18653324).

20518564 is a wasteful number, since it uses less digits than its factorization.

20518564 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 466346 (or 466344 counting only the distinct ones).

The product of its (nonzero) digits is 9600, while the sum is 31.

The square root of 20518564 is about 4529.7421560173. The cubic root of 20518564 is about 273.7677716895.

It can be divided in two parts, 205 and 18564, that added together give a square (18769 = 137²).

The spelling of 20518564 in words is "twenty million, five hundred eighteen thousand, five hundred sixty-four".