18312216 has 32 divisors (see below), whose sum is σ = 49302960. Its totient is φ = 5634432.

The previous prime is 18312167. The next prime is 18312233. The reversal of 18312216 is 61221381.

It is a Harshad number since it is a multiple of its sum of digits (24).

It is a nude number because it is divisible by every one of its digits.

It is a congruent number.

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 29035 + ... + 29658.

Almost surely, 2^18312216 is an apocalyptic number.

It is an amenable number.

18312216 is an abundant number, since it is smaller than the sum of its proper divisors (30990744).

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

18312216 is a wasteful number, since it uses less digits than its factorization.

18312216 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 58715 (or 58711 counting only the distinct ones).

The product of its digits is 576, while the sum is 24.

The square root of 18312216 is about 4279.2775091130. The cubic root of 18312216 is about 263.5807164502.

Adding to 18312216 its reverse (61221381), we get a palindrome (79533597).

It can be divided in two parts, 18312 and 216, that added together give a triangular number (18528 = T₁₉₂).

The spelling of 18312216 in words is "eighteen million, three hundred twelve thousand, two hundred sixteen".