18131857 has 2 divisors, whose sum is σ = 18131858. Its totient is φ = 18131856.

The previous prime is 18131831. The next prime is 18131879. The reversal of 18131857 is 75813181.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 15968016 + 2163841 = 3996^2 + 1471^2 .

It is a cyclic number.

It is not a de Polignac number, because 18131857 - 2²³ = 9743249 is a prime.

It is not a weakly prime, because it can be changed into another prime (18131557) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 9065928 + 9065929.

It is an arithmetic number, because the mean of its divisors is an integer number (9065929).

Almost surely, 2^18131857 is an apocalyptic number.

It is an amenable number.

18131857 is a deficient number, since it is larger than the sum of its proper divisors (1).

18131857 is an equidigital number, since it uses as much as digits as its factorization.

18131857 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 6720, while the sum is 34.

The square root of 18131857 is about 4258.1518291390. The cubic root of 18131857 is about 262.7125148294.

The spelling of 18131857 in words is "eighteen million, one hundred thirty-one thousand, eight hundred fifty-seven".