91025017681 has 16 divisors (see below), whose sum is σ = 100691642128. Its totient is φ = 81739756800.

The previous prime is 91025017663. The next prime is 91025017687. The reversal of 91025017681 is 18671052019.

It is a happy number.

It can be written as a sum of positive squares in 8 ways, for example, as 12714592081 + 78310425600 = 112759^2 + 279840^2 .

It is not a de Polignac number, because 91025017681 - 2⁷ = 91025017553 is a prime.

It is a super-2 number, since 2×91025017681² (a number of 23 digits) contains 22 as substring.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (91025017687) by changing a digit.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 4868491 + ... + 4887151.

It is an arithmetic number, because the mean of its divisors is an integer number (6293227633).

Almost surely, 2^91025017681 is an apocalyptic number.

It is an amenable number.

91025017681 is a deficient number, since it is larger than the sum of its proper divisors (9666624447).

91025017681 is a wasteful number, since it uses less digits than its factorization.

91025017681 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 28852.

The product of its (nonzero) digits is 30240, while the sum is 40.

The spelling of 91025017681 in words is "ninety-one billion, twenty-five million, seventeen thousand, six hundred eighty-one".