20564428 has 12 divisors (see below), whose sum is σ = 36066240. Its totient is φ = 10259792.

The previous prime is 20564399. The next prime is 20564431. The reversal of 20564428 is 82446502.

It is a self number, because there is not a number n which added to its sum of digits gives 20564428.

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 3451 + ... + 7282.

It is an arithmetic number, because the mean of its divisors is an integer number (3005520).

Almost surely, 2^20564428 is an apocalyptic number.

It is an amenable number.

20564428 is a deficient number, since it is larger than the sum of its proper divisors (15501812).

20564428 is a wasteful number, since it uses less digits than its factorization.

20564428 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 11216 (or 11214 counting only the distinct ones).

The product of its (nonzero) digits is 15360, while the sum is 31.

The square root of 20564428 is about 4534.8018699829. The cubic root of 20564428 is about 273.9715991661.

The spelling of 20564428 in words is "twenty million, five hundred sixty-four thousand, four hundred twenty-eight".