18312290 has 16 divisors (see below), whose sum is σ = 33360768. Its totient is φ = 7236336.

The previous prime is 18312263. The next prime is 18312319. The reversal of 18312290 is 9221381.

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, 10202 + ... + 11861.

It is an arithmetic number, because the mean of its divisors is an integer number (2085048).

Almost surely, 2^18312290 is an apocalyptic number.

18312290 is a gapful number since it is divisible by the number (10) formed by its first and last digit.

18312290 is a deficient number, since it is larger than the sum of its proper divisors (15048478).

18312290 is a wasteful number, since it uses less digits than its factorization.

18312290 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 22153.

The product of its (nonzero) digits is 864, while the sum is 26.

The square root of 18312290 is about 4279.2861554236. The cubic root of 18312290 is about 263.5810714946.

Subtracting from 18312290 its reverse (9221381), we obtain a palindrome (9090909).

The spelling of 18312290 in words is "eighteen million, three hundred twelve thousand, two hundred ninety".