18639975 has 12 divisors (see below), whose sum is σ = 30818216. Its totient is φ = 9941280.

The previous prime is 18639967. The next prime is 18639979. The reversal of 18639975 is 57993681.

It is not a de Polignac number, because 18639975 - 2³ = 18639967 is a prime.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (18639979) 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 11 ways as a sum of consecutive naturals, for example, 124192 + ... + 124341.

Almost surely, 2^18639975 is an apocalyptic number.

18639975 is a gapful number since it is divisible by the number (15) formed by its first and last digit.

18639975 is a deficient number, since it is larger than the sum of its proper divisors (12178241).

18639975 is a wasteful number, since it uses less digits than its factorization.

18639975 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 248546 (or 248541 counting only the distinct ones).

The product of its digits is 408240, while the sum is 48.

The square root of 18639975 is about 4317.4037337270. The cubic root of 18639975 is about 265.1439825129.

The spelling of 18639975 in words is "eighteen million, six hundred thirty-nine thousand, nine hundred seventy-five".