18978904 has 16 divisors (see below), whose sum is σ = 40669200. Its totient is φ = 8133792.

The previous prime is 18978901. The next prime is 18978917. The reversal of 18978904 is 40987981.

It is a happy number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (18978901) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 169399 + ... + 169510.

It is an arithmetic number, because the mean of its divisors is an integer number (2541825).

Almost surely, 2^18978904 is an apocalyptic number.

18978904 is a gapful number since it is divisible by the number (14) formed by its first and last digit.

It is an amenable number.

18978904 is an abundant number, since it is smaller than the sum of its proper divisors (21690296).

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

18978904 is a wasteful number, since it uses less digits than its factorization.

18978904 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 338922 (or 338918 counting only the distinct ones).

The product of its (nonzero) digits is 145152, while the sum is 46.

The square root of 18978904 is about 4356.4783942997. The cubic root of 18978904 is about 266.7413693490.

It can be divided in two parts, 1897 and 8904, that added together give a palindrome (10801).

The spelling of 18978904 in words is "eighteen million, nine hundred seventy-eight thousand, nine hundred four".