91181979 has 12 divisors (see below), whose sum is σ = 150522736. Its totient is φ = 52103952.

The previous prime is 91181977. The next prime is 91182001. The reversal of 91181979 is 97918119.

It is not a de Polignac number, because 91181979 - 2¹ = 91181977 is a prime.

It is not an unprimeable number, because it can be changed into a prime (91181977) 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 11 ways as a sum of consecutive naturals, for example, 723604 + ... + 723729.

Almost surely, 2^91181979 is an apocalyptic number.

91181979 is a deficient number, since it is larger than the sum of its proper divisors (59340757).

91181979 is a wasteful number, since it uses less digits than its factorization.

91181979 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1447346 (or 1447343 counting only the distinct ones).

The product of its digits is 40824, while the sum is 45.

The square root of 91181979 is about 9548.9255416513. The cubic root of 91181979 is about 450.0937730504.

The spelling of 91181979 in words is "ninety-one million, one hundred eighty-one thousand, nine hundred seventy-nine".