20940904 has 8 divisors (see below), whose sum is σ = 39264210. Its totient is φ = 10470448.

The previous prime is 20940901. The next prime is 20940967. The reversal of 20940904 is 40904902.

It can be written as a sum of positive squares in only one way, i.e., 13704804 + 7236100 = 3702^2 + 2690^2 .

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 not an unprimeable number, because it can be changed into a prime (20940901) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 1308799 + ... + 1308814.

Almost surely, 2^20940904 is an apocalyptic number.

It is an amenable number.

20940904 is a deficient number, since it is larger than the sum of its proper divisors (18323306).

20940904 is a wasteful number, since it uses less digits than its factorization.

20940904 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 2617619 (or 2617615 counting only the distinct ones).

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

The square root of 20940904 is about 4576.1232500884. The cubic root of 20940904 is about 275.6333786529.

The spelling of 20940904 in words is "twenty million, nine hundred forty thousand, nine hundred four".