18689988 has 12 divisors (see below), whose sum is σ = 43610000. Its totient is φ = 6229992.

The previous prime is 18689963. The next prime is 18689989. The reversal of 18689988 is 88998681.

It is a tau number, because it is divible by the number of its divisors (12).

It is not an unprimeable number, because it can be changed into a prime (18689989) 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 3 ways as a sum of consecutive naturals, for example, 778738 + ... + 778761.

Almost surely, 2^18689988 is an apocalyptic number.

It is an amenable number.

18689988 is an abundant number, since it is smaller than the sum of its proper divisors (24920012).

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

18689988 is a wasteful number, since it uses less digits than its factorization.

18689988 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1557506 (or 1557504 counting only the distinct ones).

The product of its digits is 1990656, while the sum is 57.

The square root of 18689988 is about 4323.1918763802. The cubic root of 18689988 is about 265.3809070750.

The spelling of 18689988 in words is "eighteen million, six hundred eighty-nine thousand, nine hundred eighty-eight".