91625968981 has 4 divisors (see below), whose sum is σ = 91626668032. Its totient is φ = 91625269932.

The previous prime is 91625968937. The next prime is 91625969003. The reversal of 91625968981 is 18986952619.

91625968981 is nontrivially palindromic in base 2 and base 4.

91625968981 is an esthetic number in base 2, because in such base its adjacent digits differ by 1.

It is a semiprime because it is the product of two primes, and also a Blum integer, because the two primes are equal to 3 mod 4, and also a brilliant number, because the two primes have the same length, and also an emirpimes, since its reverse is a distinct semiprime: 18986952619 = 179 ⋅106072361.

It is a 3-Lehmer number, since φ(91625968981) divides (91625968981-1)³.

It is a cyclic number.

It is not a de Polignac number, because 91625968981 - 2¹⁹ = 91625444693 is a prime.

It is a super-2 number, since 2×91625968981² (a number of 23 digits) contains 22 as substring.

It is the 38-th Jacobsthal number.

It is a Duffinian number.

91625968981 is an undulating number in base 2.

91625968981 is a nontrivial repdigit in base 4.

It is a plaindrome in base 4 and base 16.

It is a nialpdrome in base 4.

It is a zygodrome in base 4.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (91625968481) by changing a digit.

It is a nontrivial repunit in base 4.

It is a pernicious number, because its binary representation contains a prime number (19) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 87381 + ... + 436906.

It is an arithmetic number, because the mean of its divisors is an integer number (22906667008).

It is a Poulet number, since it divides 2^91625968980-1.

Almost surely, 2^91625968981 is an apocalyptic number.

91625968981 is the 174763-rd octagonal number.

It is an amenable number.

91625968981 is a deficient number, since it is larger than the sum of its proper divisors (699051).

91625968981 is a wasteful number, since it uses less digits than its factorization.

91625968981 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 699050.

The product of its digits is 16796160, while the sum is 64.

The spelling of 91625968981 in words is "ninety-one billion, six hundred twenty-five million, nine hundred sixty-eight thousand, nine hundred eighty-one".