20901904 has 20 divisors (see below), whose sum is σ = 40650300. Its totient is φ = 10411520.

The previous prime is 20901901. The next prime is 20901911. The reversal of 20901904 is 40910902.

It can be written as a sum of positive squares in 2 ways, for example, as 18079504 + 2822400 = 4252^2 + 1680^2 .

It is not an unprimeable number, because it can be changed into a prime (20901901) by changing a digit.

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 in 3 ways as a sum of consecutive naturals, for example, 2172 + ... + 6820.

It is an arithmetic number, because the mean of its divisors is an integer number (2032515).

Almost surely, 2^20901904 is an apocalyptic number.

It is an amenable number.

20901904 is a deficient number, since it is larger than the sum of its proper divisors (19748396).

20901904 is a wasteful number, since it uses less digits than its factorization.

20901904 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 4938 (or 4932 counting only the distinct ones).

The product of its (nonzero) digits is 648, while the sum is 25.

The square root of 20901904 is about 4571.8600153548. The cubic root of 20901904 is about 275.4621606062.

The spelling of 20901904 in words is "twenty million, nine hundred one thousand, nine hundred four".