18345181 has 4 divisors (see below), whose sum is σ = 18735552. Its totient is φ = 17954812.

The previous prime is 18345179. The next prime is 18345199. The reversal of 18345181 is 18154381.

It is a semiprime because it is the product of two primes, and also a Blum integer, because the two primes are equal to 3 mod 4.

It is a cyclic number.

It is not a de Polignac number, because 18345181 - 2¹ = 18345179 is a prime.

It is a super-2 number, since 2×18345181² = 673091331845522, which contains 22 as substring.

It is a Smith number, since the sum of its digits (31) coincides with the sum of the digits of its prime factors. Since it is squarefree, it is also a hoax number.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (18345101) 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, 195115 + ... + 195208.

It is an arithmetic number, because the mean of its divisors is an integer number (4683888).

Almost surely, 2^18345181 is an apocalyptic number.

It is an amenable number.

18345181 is a deficient number, since it is larger than the sum of its proper divisors (390371).

18345181 is an equidigital number, since it uses as much as digits as its factorization.

18345181 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 390370.

The product of its digits is 3840, while the sum is 31.

The square root of 18345181 is about 4283.1274788407. The cubic root of 18345181 is about 263.7387845159.

The spelling of 18345181 in words is "eighteen million, three hundred forty-five thousand, one hundred eighty-one".