18664431 has 16 divisors (see below), whose sum is σ = 26105856. Its totient is φ = 11838816.

The previous prime is 18664417. The next prime is 18664433. The reversal of 18664431 is 13446681.

It is not a de Polignac number, because 18664431 - 2⁶ = 18664367 is a prime.

It is a super-2 number, since 2×18664431² = 696721969107522, which contains 22 as substring.

It is a junction number, because it is equal to n+sod(n) for n = 18664392 and 18664401.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (18664433) by changing a digit.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 14781 + ... + 15993.

It is an arithmetic number, because the mean of its divisors is an integer number (1631616).

Almost surely, 2^18664431 is an apocalyptic number.

18664431 is a deficient number, since it is larger than the sum of its proper divisors (7441425).

18664431 is a wasteful number, since it uses less digits than its factorization.

18664431 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1462.

The product of its digits is 13824, while the sum is 33.

The square root of 18664431 is about 4320.2350630492. The cubic root of 18664431 is about 265.2598898113.

The spelling of 18664431 in words is "eighteen million, six hundred sixty-four thousand, four hundred thirty-one".