91181140 has 24 divisors (see below), whose sum is σ = 191940840. Its totient is φ = 36384768.

The previous prime is 91181119. The next prime is 91181141. The reversal of 91181140 is 4118119.

It can be written as a sum of positive squares in 4 ways, for example, as 6320196 + 84860944 = 2514^2 + 9212^2 .

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (91181141) 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 7 ways as a sum of consecutive naturals, for example, 3396 + ... + 13924.

It is an arithmetic number, because the mean of its divisors is an integer number (7997535).

Almost surely, 2^91181140 is an apocalyptic number.

It is an amenable number.

91181140 is an abundant number, since it is smaller than the sum of its proper divisors (100759700).

It is a pseudoperfect number, because it is the sum of a subset of its proper divisors.

91181140 is a wasteful number, since it uses less digits than its factorization.

91181140 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 10971 (or 10969 counting only the distinct ones).

The product of its (nonzero) digits is 288, while the sum is 25.

The square root of 91181140 is about 9548.8816099059. The cubic root of 91181140 is about 450.0923925516.

Adding to 91181140 its reverse (4118119), we get a palindrome (95299259).

It can be divided in two parts, 9118 and 1140, that multiplied together give a triangular number (10394520 = T₄₅₅₉).

The spelling of 91181140 in words is "ninety-one million, one hundred eighty-one thousand, one hundred forty".