18155172 has 24 divisors (see below), whose sum is σ = 48414016. Its totient is φ = 5187168.

The previous prime is 18155161. The next prime is 18155209. The reversal of 18155172 is 27155181.

It is a super-2 number, since 2×18155172² = 659220540699168, which contains 22 as substring.

It is a Smith number, since the sum of its digits (30) coincides with the sum of the digits of its prime factors.

It is an unprimeable number.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 107983 + ... + 108150.

Almost surely, 2^18155172 is an apocalyptic number.

18155172 is a gapful number since it is divisible by the number (12) formed by its first and last digit.

It is an amenable number.

18155172 is an abundant number, since it is smaller than the sum of its proper divisors (30258844).

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

18155172 is a wasteful number, since it uses less digits than its factorization.

18155172 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 216147 (or 216145 counting only the distinct ones).

The product of its digits is 2800, while the sum is 30.

The square root of 18155172 is about 4260.8886397089. Note that the first 3 decimals coincide. The cubic root of 18155172 is about 262.8250702947.

Subtracting 18155172 from its reverse (27155181), we obtain a palindrome (9000009).

The spelling of 18155172 in words is "eighteen million, one hundred fifty-five thousand, one hundred seventy-two".