20618904 has 16 divisors (see below), whose sum is σ = 51547320. Its totient is φ = 6872960.

The previous prime is 20618903. The next prime is 20618929. The reversal of 20618904 is 40981602.

It is a super-2 number, since 2×20618904² = 850278404322432, which contains 22 as substring.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (20618903) 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 in 3 ways as a sum of consecutive naturals, for example, 429537 + ... + 429584.

Almost surely, 2^20618904 is an apocalyptic number.

20618904 is a gapful number since it is divisible by the number (24) formed by its first and last digit.

It is an amenable number.

20618904 is an abundant number, since it is smaller than the sum of its proper divisors (30928416).

It is a pseudoperfect number, because it is the sum of a subset of its proper divisors.

20618904 is a wasteful number, since it uses less digits than its factorization.

20618904 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 859130 (or 859126 counting only the distinct ones).

The product of its (nonzero) digits is 3456, while the sum is 30.

The square root of 20618904 is about 4540.8043340360. The cubic root of 20618904 is about 274.2133064698.

It can be divided in two parts, 206 and 18904, that added together give a triangular number (19110 = T₁₉₅).

The spelling of 20618904 in words is "twenty million, six hundred eighteen thousand, nine hundred four".