18516868687 has 2 divisors, whose sum is σ = 18516868688. Its totient is φ = 18516868686.

The previous prime is 18516868621. The next prime is 18516868751. The reversal of 18516868687 is 78686861581.

It is a happy number.

It is an a-pointer prime, because the next prime (18516868751) can be obtained adding 18516868687 to its sum of digits (64).

It is a strong prime.

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-18516868687 is a prime.

It is a super-2 number, since 2×18516868687² (a number of 21 digits) contains 22 as substring.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (18516868607) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 9258434343 + 9258434344.

It is an arithmetic number, because the mean of its divisors is an integer number (9258434344).

Almost surely, 2^18516868687 is an apocalyptic number.

18516868687 is a deficient number, since it is larger than the sum of its proper divisors (1).

18516868687 is an equidigital number, since it uses as much as digits as its factorization.

18516868687 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 30965760, while the sum is 64.

The spelling of 18516868687 in words is "eighteen billion, five hundred sixteen million, eight hundred sixty-eight thousand, six hundred eighty-seven".