18639408 has 40 divisors (see below), whose sum is σ = 48306928. Its totient is φ = 6193152.

The previous prime is 18639403. The next prime is 18639419. The reversal of 18639408 is 80493681.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (18639403) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 27360 + ... + 28032.

Almost surely, 2^18639408 is an apocalyptic number.

It is an amenable number.

18639408 is an abundant number, since it is smaller than the sum of its proper divisors (29667520).

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

18639408 is a wasteful number, since it uses less digits than its factorization.

18639408 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1261 (or 1255 counting only the distinct ones).

The product of its (nonzero) digits is 41472, while the sum is 39.

The square root of 18639408 is about 4317.3380687641. The cubic root of 18639408 is about 265.1412940586.

The spelling of 18639408 in words is "eighteen million, six hundred thirty-nine thousand, four hundred eight".