18316681 has 2 divisors, whose sum is σ = 18316682. Its totient is φ = 18316680.

The previous prime is 18316673. The next prime is 18316693. The reversal of 18316681 is 18661381.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 13388281 + 4928400 = 3659^2 + 2220^2 .

It is a cyclic number.

It is not a de Polignac number, because 18316681 - 2³ = 18316673 is a prime.

It is a super-2 number, since 2×18316681² = 671001605711522, which contains 22 as substring.

It is not a weakly prime, because it can be changed into another prime (18316601) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 9158340 + 9158341.

It is an arithmetic number, because the mean of its divisors is an integer number (9158341).

Almost surely, 2^18316681 is an apocalyptic number.

It is an amenable number.

18316681 is a deficient number, since it is larger than the sum of its proper divisors (1).

18316681 is an equidigital number, since it uses as much as digits as its factorization.

18316681 is an evil number, because the sum of its binary digits is even.

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

The square root of 18316681 is about 4279.7991775316. The cubic root of 18316681 is about 263.6021373469.

The spelling of 18316681 in words is "eighteen million, three hundred sixteen thousand, six hundred eighty-one".