18718431 has 16 divisors (see below), whose sum is σ = 25426560. Its totient is φ = 12247200.

The previous prime is 18718417. The next prime is 18718433. The reversal of 18718431 is 13481781.

It is not a de Polignac number, because 18718431 - 2¹⁰ = 18717407 is a prime.

It is a super-2 number, since 2×18718431² = 700759318203522, which contains 22 as substring.

It is a junction number, because it is equal to n+sod(n) for n = 18718392 and 18718401.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (18718433) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 49200 + ... + 49578.

It is an arithmetic number, because the mean of its divisors is an integer number (1589160).

Almost surely, 2^18718431 is an apocalyptic number.

18718431 is a deficient number, since it is larger than the sum of its proper divisors (6708129).

18718431 is a wasteful number, since it uses less digits than its factorization.

18718431 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 646.

The product of its digits is 5376, while the sum is 33.

The square root of 18718431 is about 4326.4802091307. The cubic root of 18718431 is about 265.5154604578.

The spelling of 18718431 in words is "eighteen million, seven hundred eighteen thousand, four hundred thirty-one".