91631779857601 has 9 divisors (see below), whose sum is σ = 91924795128649. Its totient is φ = 91339695721264.

The previous prime is 91631779857587. The next prime is 91631779857623. The reversal of 91631779857601 is 10675897713619.

The square root of 91631779857601 is 9572449.

It is a perfect power (a square), and thus also a powerful number.

It can be written as a sum of positive squares in 4 ways, for example, as 46840349688001 + 44791430169600 = 6844001^2 + 6692640^2 .

It is not a de Polignac number, because 91631779857601 - 2⁷ = 91631779857473 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (91631779852601) by changing a digit.

It is a polite number, since it can be written in 8 ways as a sum of consecutive naturals, for example, 3034451235 + ... + 3034481431.

Almost surely, 2^{91631779857601} is an apocalyptic number.

91631779857601 is the 9572449-th square number.

91631779857601 is the 4786225-th centered octagonal number.

It is an amenable number.

91631779857601 is a deficient number, since it is larger than the sum of its proper divisors (293015271048).

91631779857601 is an frugal number, since it uses more digits than its factorization.

91631779857601 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 61028 (or 30514 counting only the distinct ones).

The product of its (nonzero) digits is 120022560, while the sum is 70.

The spelling of 91631779857601 in words is "ninety-one trillion, six hundred thirty-one billion, seven hundred seventy-nine million, eight hundred fifty-seven thousand, six hundred one".