18215988 has 48 divisors (see below), whose sum is σ = 49897344. Its totient is φ = 5063040.

The previous prime is 18215983. The next prime is 18216017. The reversal of 18215988 is 88951281.

It is a super-2 number, since 2×18215988² = 663644437632288, which contains 22 as substring.

It is a hoax number, since the sum of its digits (42) coincides with the sum of the digits of its distinct prime factors.

It is a Harshad number since it is a multiple of its sum of digits (42).

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (18215983) 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, 178 + ... + 6038.

It is an arithmetic number, because the mean of its divisors is an integer number (1039528).

Almost surely, 2^18215988 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 18215988, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (24948672).

18215988 is an abundant number, since it is smaller than the sum of its proper divisors (31681356).

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

18215988 is a wasteful number, since it uses less digits than its factorization.

18215988 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 5912 (or 5910 counting only the distinct ones).

The product of its digits is 46080, while the sum is 42.

The square root of 18215988 is about 4268.0192127028. The cubic root of 18215988 is about 263.1182127478.

The spelling of 18215988 in words is "eighteen million, two hundred fifteen thousand, nine hundred eighty-eight".