18431688 has 64 divisors (see below), whose sum is σ = 50771520. Its totient is φ = 5575680.

The previous prime is 18431681. The next prime is 18431711. The reversal of 18431688 is 88613481.

It is a nude number because it is divisible by every one of its digits.

It is not an unprimeable number, because it can be changed into a prime (18431681) 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, 31656 + ... + 32232.

It is an arithmetic number, because the mean of its divisors is an integer number (793305).

Almost surely, 2^18431688 is an apocalyptic number.

It is an amenable number.

It is a practical number, because each smaller number is the sum of distinct divisors of 18431688, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (25385760).

18431688 is an abundant number, since it is smaller than the sum of its proper divisors (32339832).

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

18431688 is a wasteful number, since it uses less digits than its factorization.

18431688 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 619 (or 593 counting only the distinct ones).

The product of its digits is 36864, while the sum is 39.

The square root of 18431688 is about 4293.2141805412. The cubic root of 18431688 is about 264.1526894499.

The spelling of 18431688 in words is "eighteen million, four hundred thirty-one thousand, six hundred eighty-eight".