18866131 has 4 divisors (see below), whose sum is σ = 19078200. Its totient is φ = 18654064.

The previous prime is 18866123. The next prime is 18866161. The reversal of 18866131 is 13166881.

It is a semiprime because it is the product of two primes.

It is a cyclic number.

It is not a de Polignac number, because 18866131 - 2³ = 18866123 is a prime.

It is a super-2 number, since 2×18866131² = 711861797818322, which contains 22 as substring.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (18866101) 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, 105901 + ... + 106078.

It is an arithmetic number, because the mean of its divisors is an integer number (4769550).

Almost surely, 2^18866131 is an apocalyptic number.

18866131 is a deficient number, since it is larger than the sum of its proper divisors (212069).

18866131 is an equidigital number, since it uses as much as digits as its factorization.

18866131 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 212068.

The product of its digits is 6912, while the sum is 34.

The square root of 18866131 is about 4343.5159721129. The cubic root of 18866131 is about 266.2119920471.

The spelling of 18866131 in words is "eighteen million, eight hundred sixty-six thousand, one hundred thirty-one".