18191212 has 12 divisors (see below), whose sum is σ = 34283536. Its totient is φ = 8395920.

The previous prime is 18191179. The next prime is 18191213. The reversal of 18191212 is 21219181.

It is not an unprimeable number, because it can be changed into a prime (18191213) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 174864 + ... + 174967.

Almost surely, 2^18191212 is an apocalyptic number.

It is an amenable number.

18191212 is a deficient number, since it is larger than the sum of its proper divisors (16092324).

18191212 is a wasteful number, since it uses less digits than its factorization.

18191212 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 349848 (or 349846 counting only the distinct ones).

The product of its digits is 288, while the sum is 25.

The square root of 18191212 is about 4265.1157076919. The cubic root of 18191212 is about 262.9988675032.

The spelling of 18191212 in words is "eighteen million, one hundred ninety-one thousand, two hundred twelve".