20397566 has 32 divisors (see below), whose sum is σ = 36968448. Its totient is φ = 8255520.

The previous prime is 20397551. The next prime is 20397571. The reversal of 20397566 is 66579302.

It is a Curzon number.

It is a congruent number.

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, 18116 + ... + 19208.

It is an arithmetic number, because the mean of its divisors is an integer number (1155264).

Almost surely, 2^20397566 is an apocalyptic number.

20397566 is a deficient number, since it is larger than the sum of its proper divisors (16570882).

20397566 is a wasteful number, since it uses less digits than its factorization.

20397566 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1176.

The product of its (nonzero) digits is 68040, while the sum is 38.

The square root of 20397566 is about 4516.3664598879. The cubic root of 20397566 is about 273.2285741053.

The spelling of 20397566 in words is "twenty million, three hundred ninety-seven thousand, five hundred sixty-six".