91556681 has 4 divisors (see below), whose sum is σ = 91579152. Its totient is φ = 91534212.

The previous prime is 91556677. The next prime is 91556693. The reversal of 91556681 is 18665519.

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 an emirpimes, since its reverse is a distinct semiprime: 18665519 = 1471 ⋅12689.

It is a cyclic number.

It is not a de Polignac number, because 91556681 - 2² = 91556677 is a prime.

It is a super-2 number, since 2×91556681² = 16765251671471522, which contains 22 as substring.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (91550681) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 3215 + ... + 13908.

It is an arithmetic number, because the mean of its divisors is an integer number (22894788).

Almost surely, 2^91556681 is an apocalyptic number.

It is an amenable number.

91556681 is a deficient number, since it is larger than the sum of its proper divisors (22471).

91556681 is a wasteful number, since it uses less digits than its factorization.

91556681 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 22470.

The product of its digits is 64800, while the sum is 41.

The square root of 91556681 is about 9568.5255394967. The cubic root of 91556681 is about 450.7094668798.

The spelling of 91556681 in words is "ninety-one million, five hundred fifty-six thousand, six hundred eighty-one".