18315540 has 72 divisors (see below), whose sum is σ = 56183400. Its totient is φ = 4829184.

The previous prime is 18315533. The next prime is 18315551. The reversal of 18315540 is 4551381.

It can be written as a sum of positive squares in 4 ways, for example, as 4743684 + 13571856 = 2178^2 + 3684^2 .

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 23 ways as a sum of consecutive naturals, for example, 16936 + ... + 17984.

It is an arithmetic number, because the mean of its divisors is an integer number (780325).

Almost surely, 2^18315540 is an apocalyptic number.

18315540 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 18315540, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (28091700).

18315540 is an abundant number, since it is smaller than the sum of its proper divisors (37867860).

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

18315540 is a wasteful number, since it uses less digits than its factorization.

18315540 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1161 (or 1156 counting only the distinct ones).

The product of its (nonzero) digits is 2400, while the sum is 27.

The square root of 18315540 is about 4279.6658748085. The cubic root of 18315540 is about 263.5966637154.

The spelling of 18315540 in words is "eighteen million, three hundred fifteen thousand, five hundred forty".