91918791 has 12 divisors (see below), whose sum is σ = 134453280. Its totient is φ = 60503040.

The previous prime is 91918747. The next prime is 91918817. The reversal of 91918791 is 19781919.

It is not a de Polignac number, because 91918791 - 2⁹ = 91918279 is a prime.

It is a Smith number, since the sum of its digits (45) coincides with the sum of the digits of its prime factors.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (91918721) by changing a digit.

It is a polite number, since it can be written in 11 ways as a sum of consecutive naturals, for example, 63930 + ... + 65351.

It is an arithmetic number, because the mean of its divisors is an integer number (11204440).

Almost surely, 2^91918791 is an apocalyptic number.

91918791 is a deficient number, since it is larger than the sum of its proper divisors (42534489).

91918791 is a wasteful number, since it uses less digits than its factorization.

91918791 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 129366 (or 129363 counting only the distinct ones).

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

The square root of 91918791 is about 9587.4288002571. The cubic root of 91918791 is about 451.3028760204.

The spelling of 91918791 in words is "ninety-one million, nine hundred eighteen thousand, seven hundred ninety-one".