91991159 has 8 divisors (see below), whose sum is σ = 99409632. Its totient is φ = 84621600.

The previous prime is 91991117. The next prime is 91991171. The reversal of 91991159 is 95119919.

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

It is a cyclic number.

It is not a de Polignac number, because 91991159 - 2¹⁶ = 91925623 is a prime.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (91991359) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 8267 + ... + 15884.

It is an arithmetic number, because the mean of its divisors is an integer number (12426204).

Almost surely, 2^91991159 is an apocalyptic number.

91991159 is a deficient number, since it is larger than the sum of its proper divisors (7418473).

91991159 is a wasteful number, since it uses less digits than its factorization.

91991159 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 24457.

The product of its digits is 32805, while the sum is 44.

The square root of 91991159 is about 9591.2021665691. The cubic root of 91991159 is about 451.4212824196.

The spelling of 91991159 in words is "ninety-one million, nine hundred ninety-one thousand, one hundred fifty-nine".