20975664 has 20 divisors (see below), whose sum is σ = 54187256. Its totient is φ = 6991872.

The previous prime is 20975663. The next prime is 20975683. The reversal of 20975664 is 46657902.

It is a hoax number, since the sum of its digits (39) coincides with the sum of the digits of its distinct prime factors.

It is not an unprimeable number, because it can be changed into a prime (20975663) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (5) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 218449 + ... + 218544.

Almost surely, 2^20975664 is an apocalyptic number.

20975664 is a gapful number since it is divisible by the number (24) formed by its first and last digit.

It is an amenable number.

20975664 is an abundant number, since it is smaller than the sum of its proper divisors (33211592).

It is a pseudoperfect number, because it is the sum of a subset of its proper divisors.

20975664 is a wasteful number, since it uses less digits than its factorization.

20975664 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 437004 (or 436998 counting only the distinct ones).

The product of its (nonzero) digits is 90720, while the sum is 39.

The square root of 20975664 is about 4579.9196499502. The cubic root of 20975664 is about 275.7858031442.

The spelling of 20975664 in words is "twenty million, nine hundred seventy-five thousand, six hundred sixty-four".