91761578017 has 2 divisors, whose sum is σ = 91761578018. Its totient is φ = 91761578016.

The previous prime is 91761577981. The next prime is 91761578119. The reversal of 91761578017 is 71087516719.

It is a happy number.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 64577482641 + 27184095376 = 254121^2 + 164876^2 .

It is a cyclic number.

It is not a de Polignac number, because 91761578017 - 2³¹ = 89614094369 is a prime.

It is not a weakly prime, because it can be changed into another prime (91761578417) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 45880789008 + 45880789009.

It is an arithmetic number, because the mean of its divisors is an integer number (45880789009).

Almost surely, 2^91761578017 is an apocalyptic number.

It is an amenable number.

91761578017 is a deficient number, since it is larger than the sum of its proper divisors (1).

91761578017 is an equidigital number, since it uses as much as digits as its factorization.

91761578017 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 740880, while the sum is 52.

The spelling of 91761578017 in words is "ninety-one billion, seven hundred sixty-one million, five hundred seventy-eight thousand, seventeen".