18988538 has 4 divisors (see below), whose sum is σ = 28482810. Its totient is φ = 9494268.

The previous prime is 18988483. The next prime is 18988573. The reversal of 18988538 is 83588981.

It is a semiprime because it is the product of two primes.

It can be written as a sum of positive squares in only one way, i.e., 15389929 + 3598609 = 3923^2 + 1897^2 .

It is an unprimeable number.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 4747133 + ... + 4747136.

Almost surely, 2^18988538 is an apocalyptic number.

18988538 is a deficient number, since it is larger than the sum of its proper divisors (9494272).

18988538 is an equidigital number, since it uses as much as digits as its factorization.

18988538 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 9494271.

The product of its digits is 552960, while the sum is 50.

The square root of 18988538 is about 4357.5839636202. The cubic root of 18988538 is about 266.7864957984.

The spelling of 18988538 in words is "eighteen million, nine hundred eighty-eight thousand, five hundred thirty-eight".