91661811 has 8 divisors (see below), whose sum is σ = 122426304. Its totient is φ = 61002600.

The previous prime is 91661777. The next prime is 91661813. The reversal of 91661811 is 11816619.

It is a sphenic number, since it is the product of 3 distinct primes.

It is not a de Polignac number, because 91661811 - 2⁶ = 91661747 is a prime.

It is not an unprimeable number, because it can be changed into a prime (91661813) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 24265 + ... + 27786.

It is an arithmetic number, because the mean of its divisors is an integer number (15303288).

Almost surely, 2^91661811 is an apocalyptic number.

91661811 is a deficient number, since it is larger than the sum of its proper divisors (30764493).

91661811 is a wasteful number, since it uses less digits than its factorization.

91661811 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 52641.

The product of its digits is 2592, while the sum is 33.

The square root of 91661811 is about 9574.0174952838. The cubic root of 91661811 is about 450.8819100098.

The spelling of 91661811 in words is "ninety-one million, six hundred sixty-one thousand, eight hundred eleven".