20665256 has 16 divisors (see below), whose sum is σ = 39006240. Its totient is φ = 10263600.

The previous prime is 20665243. The next prime is 20665259. The reversal of 20665256 is 65256602.

It is not an unprimeable number, because it can be changed into a prime (20665259) by changing a digit.

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, 7346 + ... + 9761.

It is an arithmetic number, because the mean of its divisors is an integer number (2437890).

Almost surely, 2^20665256 is an apocalyptic number.

It is an amenable number.

20665256 is a deficient number, since it is larger than the sum of its proper divisors (18340984).

20665256 is a wasteful number, since it uses less digits than its factorization.

20665256 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 17264 (or 17260 counting only the distinct ones).

The product of its (nonzero) digits is 21600, while the sum is 32.

The square root of 20665256 is about 4545.9054103666. The cubic root of 20665256 is about 274.4186329772.

The spelling of 20665256 in words is "twenty million, six hundred sixty-five thousand, two hundred fifty-six".