18315216 has 30 divisors (see below), whose sum is σ = 51257570. Its totient is φ = 6105024.

The previous prime is 18315197. The next prime is 18315217. The reversal of 18315216 is 61251381.

It can be written as a sum of positive squares in only one way, i.e., 10497600 + 7817616 = 3240^2 + 2796^2 .

It is a self number, because there is not a number n which added to its sum of digits gives 18315216.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (18315217) by changing a digit.

It is a polite number, since it can be written in 5 ways as a sum of consecutive naturals, for example, 63451 + ... + 63738.

Almost surely, 2^18315216 is an apocalyptic number.

18315216 is a gapful number since it is divisible by the number (16) formed by its first and last digit.

It is an amenable number.

18315216 is an abundant number, since it is smaller than the sum of its proper divisors (32942354).

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

18315216 is a wasteful number, since it uses less digits than its factorization.

18315216 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 127203 (or 127194 counting only the distinct ones).

The product of its digits is 1440, while the sum is 27.

The square root of 18315216 is about 4279.6280212187. The cubic root of 18315216 is about 263.5951093737.

Adding to 18315216 its reverse (61251381), we get a palindrome (79566597).

The spelling of 18315216 in words is "eighteen million, three hundred fifteen thousand, two hundred sixteen".