91580981 has 4 divisors (see below), whose sum is σ = 91733964. Its totient is φ = 91428000.

The previous prime is 91580939. The next prime is 91580999. The reversal of 91580981 is 18908519.

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 52330756 + 39250225 = 7234^2 + 6265^2 .

It is a cyclic number.

It is not a de Polignac number, because 91580981 - 2¹⁸ = 91318837 is a prime.

It is a super-2 number, since 2×91580981² = 16774152161844722, which contains 22 as substring.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (91580681) 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, 75590 + ... + 76791.

It is an arithmetic number, because the mean of its divisors is an integer number (22933491).

Almost surely, 2^91580981 is an apocalyptic number.

It is an amenable number.

91580981 is a deficient number, since it is larger than the sum of its proper divisors (152983).

91580981 is a wasteful number, since it uses less digits than its factorization.

91580981 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 152982.

The product of its (nonzero) digits is 25920, while the sum is 41.

The square root of 91580981 is about 9569.7952433686. The cubic root of 91580981 is about 450.7493375229.

The spelling of 91580981 in words is "ninety-one million, five hundred eighty thousand, nine hundred eighty-one".