91881 has 16 divisors (see below), whose sum is σ = 141120. Its totient is φ = 59040.

The previous prime is 91873. The next prime is 91909. The reversal of 91881 is 18819.

91881 = T₁ + T₂ + ... + T₈₁.

91881 is a nontrivial binomial coefficient, being equal to C(83, 3).

It is not a de Polignac number, because 91881 - 2³ = 91873 is a prime.

It is a super-2 number, since 2×91881² = 16884236322, which contains 22 as substring.

It is a Harshad number since it is a multiple of its sum of digits (27).

It is a Curzon number.

It is a plaindrome in base 14.

It is an inconsummate number, since it does not exist a number n which divided by its sum of digits gives 91881.

It is not an unprimeable number, because it can be changed into a prime (91801) by changing a digit.

It is the 81-st tetrahedral number.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 1066 + ... + 1148.

It is an arithmetic number, because the mean of its divisors is an integer number (8820).

2⁹¹⁸⁸¹ is an apocalyptic number.

It is an amenable number.

91881 is a deficient number, since it is larger than the sum of its proper divisors (49239).

91881 is a wasteful number, since it uses less digits than its factorization.

91881 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 133 (or 127 counting only the distinct ones).

The product of its digits is 576, while the sum is 27.

The square root of 91881 is about 303.1187885962. The cubic root of 91881 is about 45.1241018792.

91881 divided by its sum of digits (27) gives a triangular number (3403 = T₈₂).

It can be divided in two parts, 918 and 81, that added together give a palindrome (999).

The spelling of 91881 in words is "ninety-one thousand, eight hundred eighty-one".