15642518917 has 2 divisors, whose sum is σ = 15642518918. Its totient is φ = 15642518916.

The previous prime is 15642518893. The next prime is 15642518921. The reversal of 15642518917 is 71981524651.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 13304699716 + 2337819201 = 115346^2 + 48351^2 .

It is an emirp because it is prime and its reverse (71981524651) is a distict prime.

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-15642518917 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (15642513917) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 7821259458 + 7821259459.

It is an arithmetic number, because the mean of its divisors is an integer number (7821259459).

Almost surely, 2^15642518917 is an apocalyptic number.

It is an amenable number.

15642518917 is a deficient number, since it is larger than the sum of its proper divisors (1).

15642518917 is an equidigital number, since it uses as much as digits as its factorization.

15642518917 is an evil number, because the sum of its binary digits is even.

The product of its digits is 604800, while the sum is 49.

The spelling of 15642518917 in words is "fifteen billion, six hundred forty-two million, five hundred eighteen thousand, nine hundred seventeen".