20564663 has 6 divisors (see below), whose sum is σ = 23922216. Its totient is φ = 17626812.

The previous prime is 20564639. The next prime is 20564717. The reversal of 20564663 is 36646502.

It is not a de Polignac number, because 20564663 - 2¹⁸ = 20302519 is a prime.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (20564603) by changing a digit.

It is a polite number, since it can be written in 5 ways as a sum of consecutive naturals, for example, 209795 + ... + 209892.

It is an arithmetic number, because the mean of its divisors is an integer number (3987036).

Almost surely, 2^20564663 is an apocalyptic number.

20564663 is a deficient number, since it is larger than the sum of its proper divisors (3357553).

20564663 is an equidigital number, since it uses as much as digits as its factorization.

20564663 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 419701 (or 419694 counting only the distinct ones).

The product of its (nonzero) digits is 25920, while the sum is 32.

The square root of 20564663 is about 4534.8277806329. The cubic root of 20564663 is about 273.9726427656.

The spelling of 20564663 in words is "twenty million, five hundred sixty-four thousand, six hundred sixty-three".