18989631 has 6 divisors (see below), whose sum is σ = 27429480. Its totient is φ = 12659748.

The previous prime is 18989627. The next prime is 18989669. The reversal of 18989631 is 13698981.

18989631 is a `hidden beast` number, since 1 + 8 + 9 + 8 + 9 + 631 = 666.

It is not a de Polignac number, because 18989631 - 2² = 18989627 is a prime.

It is a super-2 number, since 2×18989631² = 721212171032322, which contains 22 as substring.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (18989671) by changing a digit.

It is a polite number, since it can be written in 5 ways as a sum of consecutive naturals, for example, 1054971 + ... + 1054988.

It is an arithmetic number, because the mean of its divisors is an integer number (4571580).

Almost surely, 2^18989631 is an apocalyptic number.

18989631 is a deficient number, since it is larger than the sum of its proper divisors (8439849).

18989631 is a wasteful number, since it uses less digits than its factorization.

18989631 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 2109965 (or 2109962 counting only the distinct ones).

The product of its digits is 93312, while the sum is 45.

The square root of 18989631 is about 4357.7093753485. The cubic root of 18989631 is about 266.7916145362.

The spelling of 18989631 in words is "eighteen million, nine hundred eighty-nine thousand, six hundred thirty-one".