20910664 has 8 divisors (see below), whose sum is σ = 39207510. Its totient is φ = 10455328.

The previous prime is 20910641. The next prime is 20910671. The reversal of 20910664 is 46601902.

It can be written as a sum of positive squares in only one way, i.e., 20629764 + 280900 = 4542^2 + 530^2 .

It is a tau number, because it is divible by the number of its divisors (8).

It is a hoax number, since the sum of its digits (28) coincides with the sum of the digits of its distinct prime factors.

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 1306909 + ... + 1306924.

Almost surely, 2^20910664 is an apocalyptic number.

It is an amenable number.

20910664 is a deficient number, since it is larger than the sum of its proper divisors (18296846).

20910664 is a wasteful number, since it uses less digits than its factorization.

20910664 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 2613839 (or 2613835 counting only the distinct ones).

The product of its (nonzero) digits is 2592, while the sum is 28.

The square root of 20910664 is about 4572.8179495799. The cubic root of 20910664 is about 275.5006373482.

The spelling of 20910664 in words is "twenty million, nine hundred ten thousand, six hundred sixty-four".