20493904 has 10 divisors (see below), whose sum is σ = 39706970. Its totient is φ = 10246944.

The previous prime is 20493901. The next prime is 20493911. The reversal of 20493904 is 40939402.

It can be written as a sum of positive squares in only one way, i.e., 20430400 + 63504 = 4520^2 + 252^2 .

It is a super-2 number, since 2×20493904² = 840000202322432, which contains 22 as substring.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (20493901) 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 as a sum of consecutive naturals, namely, 640419 + ... + 640450.

It is an arithmetic number, because the mean of its divisors is an integer number (3970697).

Almost surely, 2^20493904 is an apocalyptic number.

It is an amenable number.

20493904 is a deficient number, since it is larger than the sum of its proper divisors (19213066).

20493904 is a wasteful number, since it uses less digits than its factorization.

20493904 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1280877 (or 1280871 counting only the distinct ones).

The product of its (nonzero) digits is 7776, while the sum is 31.

The square root of 20493904 is about 4527.0193284323. The cubic root of 20493904 is about 273.6580528410.

The spelling of 20493904 in words is "twenty million, four hundred ninety-three thousand, nine hundred four".