813984997517 has 2 divisors, whose sum is σ = 813984997518. Its totient is φ = 813984997516.

The previous prime is 813984997417. The next prime is 813984997523. The reversal of 813984997517 is 715799489318.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 590148140521 + 223836856996 = 768211^2 + 473114^2 .

It is a cyclic number.

It is not a de Polignac number, because 813984997517 - 2²⁰ = 813983948941 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (813984997537) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 406992498758 + 406992498759.

It is an arithmetic number, because the mean of its divisors is an integer number (406992498759).

Almost surely, 2^813984997517 is an apocalyptic number.

It is an amenable number.

813984997517 is a deficient number, since it is larger than the sum of its proper divisors (1).

813984997517 is an equidigital number, since it uses as much as digits as its factorization.

813984997517 is an evil number, because the sum of its binary digits is even.

The product of its digits is 137168640, while the sum is 71.

The spelling of 813984997517 in words is "eight hundred thirteen billion, nine hundred eighty-four million, nine hundred ninety-seven thousand, five hundred seventeen".