18315520 has 72 divisors (see below), whose sum is σ = 45070200. Its totient is φ = 7127040.

The previous prime is 18315509. The next prime is 18315529. The reversal of 18315520 is 2551381.

It is a happy number.

It can be written as a sum of positive squares in 4 ways, for example, as 473344 + 17842176 = 688^2 + 4224^2 .

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (18315529) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 52306 + ... + 52654.

It is an arithmetic number, because the mean of its divisors is an integer number (625975).

Almost surely, 2^18315520 is an apocalyptic number.

18315520 is a gapful number since it is divisible by the number (10) formed by its first and last digit.

It is an amenable number.

It is a practical number, because each smaller number is the sum of distinct divisors of 18315520, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (22535100).

18315520 is an abundant number, since it is smaller than the sum of its proper divisors (26754680).

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

18315520 is an equidigital number, since it uses as much as digits as its factorization.

18315520 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 411 (or 397 counting only the distinct ones).

The product of its (nonzero) digits is 1200, while the sum is 25.

The square root of 18315520 is about 4279.6635381768. The cubic root of 18315520 is about 263.5965677689.

The spelling of 18315520 in words is "eighteen million, three hundred fifteen thousand, five hundred twenty".