18939478 has 16 divisors (see below), whose sum is σ = 28881216. Its totient is φ = 9313920.

The previous prime is 18939457. The next prime is 18939491. The reversal of 18939478 is 87493981.

It is a happy number.

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 7 ways as a sum of consecutive naturals, for example, 40675 + ... + 41137.

It is an arithmetic number, because the mean of its divisors is an integer number (1805076).

Almost surely, 2^18939478 is an apocalyptic number.

18939478 is a deficient number, since it is larger than the sum of its proper divisors (9941738).

18939478 is a wasteful number, since it uses less digits than its factorization.

18939478 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 759.

The product of its digits is 435456, while the sum is 49.

The square root of 18939478 is about 4351.9510567101. The cubic root of 18939478 is about 266.5565354257.

The spelling of 18939478 in words is "eighteen million, nine hundred thirty-nine thousand, four hundred seventy-eight".