18881216 has 28 divisors (see below), whose sum is σ = 38270688. Its totient is φ = 9238272.

The previous prime is 18881209. The next prime is 18881221. The reversal of 18881216 is 61218881.

It is a hoax number, since the sum of its digits (35) coincides with the sum of the digits of its distinct prime factors.

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (7) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 131 + ... + 6146.

Almost surely, 2^18881216 is an apocalyptic number.

18881216 is a gapful number since it is divisible by the number (16) formed by its first and last digit.

It is an amenable number.

18881216 is an abundant number, since it is smaller than the sum of its proper divisors (19389472).

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

18881216 is an equidigital number, since it uses as much as digits as its factorization.

18881216 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 6336 (or 6326 counting only the distinct ones).

The product of its digits is 6144, while the sum is 35.

The square root of 18881216 is about 4345.2521215690. The cubic root of 18881216 is about 266.2829258288.

The spelling of 18881216 in words is "eighteen million, eight hundred eighty-one thousand, two hundred sixteen".