18639398 has 16 divisors (see below), whose sum is σ = 28665360. Its totient is φ = 9086976.

The previous prime is 18639391. The next prime is 18639403. The reversal of 18639398 is 89393681.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (18639391) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 15590 + ... + 16742.

It is an arithmetic number, because the mean of its divisors is an integer number (1791585).

Almost surely, 2^18639398 is an apocalyptic number.

18639398 is a deficient number, since it is larger than the sum of its proper divisors (10025962).

18639398 is a wasteful number, since it uses less digits than its factorization.

18639398 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1351.

The product of its digits is 279936, while the sum is 47.

The square root of 18639398 is about 4317.3369106429. The cubic root of 18639398 is about 265.1412466427.

The spelling of 18639398 in words is "eighteen million, six hundred thirty-nine thousand, three hundred ninety-eight".