18516131 has 2 divisors, whose sum is σ = 18516132. Its totient is φ = 18516130.

The previous prime is 18516097. The next prime is 18516139. The reversal of 18516131 is 13161581.

It is a strong prime.

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-18516131 is a prime.

It is a super-2 number, since 2×18516131² = 685694214418322, which contains 22 as substring.

It is a Sophie Germain prime.

It is a self number, because there is not a number n which added to its sum of digits gives 18516131.

It is not a weakly prime, because it can be changed into another prime (18516139) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 9258065 + 9258066.

It is an arithmetic number, because the mean of its divisors is an integer number (9258066).

Almost surely, 2^18516131 is an apocalyptic number.

18516131 is a deficient number, since it is larger than the sum of its proper divisors (1).

18516131 is an equidigital number, since it uses as much as digits as its factorization.

18516131 is an evil number, because the sum of its binary digits is even.

The product of its digits is 720, while the sum is 26.

The square root of 18516131 is about 4303.0374155938. The cubic root of 18516131 is about 264.5554716578. Note that the first 3 decimals are identical.

The spelling of 18516131 in words is "eighteen million, five hundred sixteen thousand, one hundred thirty-one".