18215918 has 16 divisors (see below), whose sum is σ = 31954560. Its totient is φ = 7625016.

The previous prime is 18215887. The next prime is 18215929. The reversal of 18215918 is 81951281.

It is a Smith number, since the sum of its digits (35) coincides with the sum of the digits of its prime factors. Since it is squarefree, it is also a hoax number.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 14528 + ... + 15731.

It is an arithmetic number, because the mean of its divisors is an integer number (1997160).

Almost surely, 2^18215918 is an apocalyptic number.

18215918 is a deficient number, since it is larger than the sum of its proper divisors (13738642).

18215918 is a wasteful number, since it uses less digits than its factorization.

18215918 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 30311.

The product of its digits is 5760, while the sum is 35.

The square root of 18215918 is about 4268.0110121695. The cubic root of 18215918 is about 263.1178757124.

The spelling of 18215918 in words is "eighteen million, two hundred fifteen thousand, nine hundred eighteen".