18215540 has 48 divisors (see below), whose sum is σ = 45626112. Its totient is φ = 5972736.

The previous prime is 18215539. The next prime is 18215543. The reversal of 18215540 is 4551281.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (18215543) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 392 + ... + 6048.

It is an arithmetic number, because the mean of its divisors is an integer number (950544).

Almost surely, 2^18215540 is an apocalyptic number.

18215540 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 18215540, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (22813056).

18215540 is an abundant number, since it is smaller than the sum of its proper divisors (27410572).

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

18215540 is a wasteful number, since it uses less digits than its factorization.

18215540 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 5696 (or 5694 counting only the distinct ones).

The product of its (nonzero) digits is 1600, while the sum is 26.

The square root of 18215540 is about 4267.9667290175. The cubic root of 18215540 is about 263.1160557063.

The spelling of 18215540 in words is "eighteen million, two hundred fifteen thousand, five hundred forty".