91159993 has 4 divisors (see below), whose sum is σ = 91223028. Its totient is φ = 91096960.

The previous prime is 91159973. The next prime is 91160011. The reversal of 91159993 is 39995119.

It is a semiprime because it is the product of two primes.

It can be written as a sum of positive squares in 2 ways, for example, as 73410624 + 17749369 = 8568^2 + 4213^2 .

It is a cyclic number.

It is not a de Polignac number, because 91159993 - 2⁵ = 91159961 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (91159903) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (19) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 29296 + ... + 32257.

It is an arithmetic number, because the mean of its divisors is an integer number (22805757).

Almost surely, 2^91159993 is an apocalyptic number.

91159993 is the 5104-th centered heptagonal number.

It is an amenable number.

91159993 is a deficient number, since it is larger than the sum of its proper divisors (63035).

91159993 is a wasteful number, since it uses less digits than its factorization.

91159993 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 63034.

The product of its digits is 98415, while the sum is 46.

The square root of 91159993 is about 9547.7742432464. The cubic root of 91159993 is about 450.0575942744.

The spelling of 91159993 in words is "ninety-one million, one hundred fifty-nine thousand, nine hundred ninety-three".