20908904 has 8 divisors (see below), whose sum is σ = 39204210. Its totient is φ = 10454448.

The previous prime is 20908883. The next prime is 20908907. The reversal of 20908904 is 40980902.

It can be written as a sum of positive squares in only one way, i.e., 14668900 + 6240004 = 3830^2 + 2498^2 .

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

It is not an unprimeable number, because it can be changed into a prime (20908907) 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 as a sum of consecutive naturals, namely, 1306799 + ... + 1306814.

Almost surely, 2^20908904 is an apocalyptic number.

It is an amenable number.

20908904 is a deficient number, since it is larger than the sum of its proper divisors (18295306).

20908904 is a wasteful number, since it uses less digits than its factorization.

20908904 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 2613619 (or 2613615 counting only the distinct ones).

The product of its (nonzero) digits is 5184, while the sum is 32.

The square root of 20908904 is about 4572.6255040185. The cubic root of 20908904 is about 275.4929077240.

It can be divided in two parts, 20908 and 904, that added together give a palindrome (21812).

The spelling of 20908904 in words is "twenty million, nine hundred eight thousand, nine hundred four".