91711899940721 has 4 divisors (see below), whose sum is σ = 92177442580212. Its totient is φ = 91246357301232.

The previous prime is 91711899940709. The next prime is 91711899940747. The reversal of 91711899940721 is 12704999811719.

It is a semiprime because it is the product of two primes.

It can be written as a sum of positive squares in 2 ways, for example, as 47083420933696 + 44628479007025 = 6861736^2 + 6680455^2 .

It is a cyclic number.

It is not a de Polignac number, because 91711899940721 - 2²² = 91711895746417 is a prime.

It is a super-2 number, since 2×91711899940721² (a number of 29 digits) contains 22 as substring.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (91711899942721) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 232771319450 + ... + 232771319843.

It is an arithmetic number, because the mean of its divisors is an integer number (23044360645053).

Almost surely, 2^{91711899940721} is an apocalyptic number.

It is an amenable number.

91711899940721 is a deficient number, since it is larger than the sum of its proper divisors (465542639491).

91711899940721 is a wasteful number, since it uses less digits than its factorization.

91711899940721 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 465542639490.

The product of its (nonzero) digits is 20575296, while the sum is 68.

The spelling of 91711899940721 in words is "ninety-one trillion, seven hundred eleven billion, eight hundred ninety-nine million, nine hundred forty thousand, seven hundred twenty-one".