991080068681 has 4 divisors (see below), whose sum is σ = 1004656508052. Its totient is φ = 977503629312.

The previous prime is 991080068669. The next prime is 991080068717. The reversal of 991080068681 is 186860080199.

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 865069268281 + 126010800400 = 930091^2 + 354980^2 .

It is a cyclic number.

It is not a de Polignac number, because 991080068681 - 2³⁴ = 973900199497 is a prime.

It is a super-2 number, since 2×991080068681² (a number of 25 digits) contains 22 as substring.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (991080068611) 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, 6788219576 + ... + 6788219721.

It is an arithmetic number, because the mean of its divisors is an integer number (251164127013).

Almost surely, 2^991080068681 is an apocalyptic number.

It is an amenable number.

991080068681 is a deficient number, since it is larger than the sum of its proper divisors (13576439371).

991080068681 is a wasteful number, since it uses less digits than its factorization.

991080068681 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 13576439370.

The product of its (nonzero) digits is 1492992, while the sum is 56.

The spelling of 991080068681 in words is "nine hundred ninety-one billion, eighty million, sixty-eight thousand, six hundred eighty-one".