91668517531 has 2 divisors, whose sum is σ = 91668517532. Its totient is φ = 91668517530.

The previous prime is 91668517489. The next prime is 91668517601. The reversal of 91668517531 is 13571586619.

It is a weak prime.

It is an emirp because it is prime and its reverse (13571586619) is a distict prime.

It is a cyclic number.

It is not a de Polignac number, because 91668517531 - 2⁷ = 91668517403 is a prime.

It is a super-3 number, since 3×91668517531³ (a number of 34 digits) contains 333 as substring. Note that it is a super-d number also for d = 2.

It is not a weakly prime, because it can be changed into another prime (91668517231) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 45834258765 + 45834258766.

It is an arithmetic number, because the mean of its divisors is an integer number (45834258766).

Almost surely, 2^91668517531 is an apocalyptic number.

91668517531 is a deficient number, since it is larger than the sum of its proper divisors (1).

91668517531 is an equidigital number, since it uses as much as digits as its factorization.

91668517531 is an evil number, because the sum of its binary digits is even.

The product of its digits is 1360800, while the sum is 52.

The spelling of 91668517531 in words is "ninety-one billion, six hundred sixty-eight million, five hundred seventeen thousand, five hundred thirty-one".