18191312 has 20 divisors (see below), whose sum is σ = 35597796. Its totient is φ = 9004800.

The previous prime is 18191311. The next prime is 18191317. The reversal of 18191312 is 21319181.

It can be written as a sum of positive squares in 2 ways, for example, as 16613776 + 1577536 = 4076^2 + 1256^2 .

It is a Smith number, since the sum of its digits (26) coincides with the sum of the digits of its prime factors.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (18191311) by changing a digit.

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 3 ways as a sum of consecutive naturals, for example, 4013 + ... + 7244.

Almost surely, 2^18191312 is an apocalyptic number.

It is an amenable number.

18191312 is a deficient number, since it is larger than the sum of its proper divisors (17406484).

18191312 is a wasteful number, since it uses less digits than its factorization.

18191312 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 11366 (or 11360 counting only the distinct ones).

The product of its digits is 432, while the sum is 26.

The square root of 18191312 is about 4265.1274306872. The cubic root of 18191312 is about 262.9993494179. Note that the first 3 decimals are identical.

The spelling of 18191312 in words is "eighteen million, one hundred ninety-one thousand, three hundred twelve".