117856881817 has 2 divisors, whose sum is σ = 117856881818. Its totient is φ = 117856881816.

The previous prime is 117856881781. The next prime is 117856881859. The reversal of 117856881817 is 718188658711.

Together with previous prime (117856881781) it forms an Ormiston pair, because they use the same digits, order apart.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 59116573321 + 58740308496 = 243139^2 + 242364^2 .

It is a cyclic number.

It is not a de Polignac number, because 117856881817 - 2²⁷ = 117722664089 is a prime.

It is not a weakly prime, because it can be changed into another prime (117856881017) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 58928440908 + 58928440909.

It is an arithmetic number, because the mean of its divisors is an integer number (58928440909).

Almost surely, 2^117856881817 is an apocalyptic number.

It is an amenable number.

117856881817 is a deficient number, since it is larger than the sum of its proper divisors (1).

117856881817 is an equidigital number, since it uses as much as digits as its factorization.

117856881817 is an evil number, because the sum of its binary digits is even.

The product of its digits is 6021120, while the sum is 61.

The spelling of 117856881817 in words is "one hundred seventeen billion, eight hundred fifty-six million, eight hundred eighty-one thousand, eight hundred seventeen".