18213181 has 8 divisors (see below), whose sum is σ = 21017984. Its totient is φ = 15459120.

The previous prime is 18213163. The next prime is 18213193. The reversal of 18213181 is 18131281.

It is a sphenic number, since it is the product of 3 distinct primes.

It is a cyclic number.

It is not a de Polignac number, because 18213181 - 2⁵ = 18213149 is a prime.

It is a super-2 number, since 2×18213181² = 663439924277522, which contains 22 as substring.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (18213101) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 11910 + ... + 13351.

It is an arithmetic number, because the mean of its divisors is an integer number (2627248).

Almost surely, 2^18213181 is an apocalyptic number.

It is an amenable number.

18213181 is a deficient number, since it is larger than the sum of its proper divisors (2804803).

18213181 is a wasteful number, since it uses less digits than its factorization.

18213181 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 25371.

The product of its digits is 384, while the sum is 25.

The square root of 18213181 is about 4267.6903589647. The cubic root of 18213181 is about 263.1046969513.

The spelling of 18213181 in words is "eighteen million, two hundred thirteen thousand, one hundred eighty-one".