20403664 has 20 divisors (see below), whose sum is σ = 39602500. Its totient is φ = 10183680.

The previous prime is 20403589. The next prime is 20403709. The reversal of 20403664 is 46630402.

It can be written as a sum of positive squares in 2 ways, for example, as 10112400 + 10291264 = 3180^2 + 3208^2 .

It is a congruent number.

It is an unprimeable number.

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 in 3 ways as a sum of consecutive naturals, for example, 15712 + ... + 16960.

It is an arithmetic number, because the mean of its divisors is an integer number (1980125).

Almost surely, 2^20403664 is an apocalyptic number.

It is an amenable number.

20403664 is a deficient number, since it is larger than the sum of its proper divisors (19198836).

20403664 is a wasteful number, since it uses less digits than its factorization.

20403664 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 2278 (or 2272 counting only the distinct ones).

The product of its (nonzero) digits is 3456, while the sum is 25.

The square root of 20403664 is about 4517.0415096609. The cubic root of 20403664 is about 273.2557992791.

The spelling of 20403664 in words is "twenty million, four hundred three thousand, six hundred sixty-four".