91056918681 has 6 divisors (see below), whose sum is σ = 131526660330. Its totient is φ = 60704612448.

The previous prime is 91056918679. The next prime is 91056918697. The reversal of 91056918681 is 18681965019.

91056918681 is a `hidden beast` number, since 9 + 1 + 0 + 569 + 18 + 68 + 1 = 666.

It can be written as a sum of positive squares in only one way, i.e., 63081345600 + 27975573081 = 251160^2 + 167259^2 .

It is not a de Polignac number, because 91056918681 - 2¹ = 91056918679 is a prime.

It is a super-2 number, since 2×91056918681² (a number of 23 digits) contains 22 as substring.

It is not an unprimeable number, because it can be changed into a prime (91056918671) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written in 5 ways as a sum of consecutive naturals, for example, 5058717696 + ... + 5058717713.

It is an arithmetic number, because the mean of its divisors is an integer number (21921110055).

Almost surely, 2^91056918681 is an apocalyptic number.

It is an amenable number.

91056918681 is a deficient number, since it is larger than the sum of its proper divisors (40469741649).

91056918681 is a wasteful number, since it uses less digits than its factorization.

91056918681 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 10117435415 (or 10117435412 counting only the distinct ones).

The product of its (nonzero) digits is 933120, while the sum is 54.

The spelling of 91056918681 in words is "ninety-one billion, fifty-six million, nine hundred eighteen thousand, six hundred eighty-one".