18231320 has 16 divisors (see below), whose sum is σ = 41020560. Its totient is φ = 7292512.

The previous prime is 18231313. The next prime is 18231331. The reversal of 18231320 is 2313281.

It is a Harshad number since it is a multiple of its sum of digits (20).

It is a junction number, because it is equal to n+sod(n) for n = 18231292 and 18231301.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 227852 + ... + 227931.

It is an arithmetic number, because the mean of its divisors is an integer number (2563785).

Almost surely, 2^18231320 is an apocalyptic number.

18231320 is a gapful number since it is divisible by the number (10) formed by its first and last digit.

It is an amenable number.

18231320 is an abundant number, since it is smaller than the sum of its proper divisors (22789240).

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

18231320 is a wasteful number, since it uses less digits than its factorization.

18231320 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 455794 (or 455790 counting only the distinct ones).

The product of its (nonzero) digits is 288, while the sum is 20.

The square root of 18231320 is about 4269.8149842821. The cubic root of 18231320 is about 263.1920123345.

The spelling of 18231320 in words is "eighteen million, two hundred thirty-one thousand, three hundred twenty".