91173989 has 8 divisors (see below), whose sum is σ = 96075840. Its totient is φ = 86282496.

The previous prime is 91173983. The next prime is 91173991. The reversal of 91173989 is 98937119.

It is a happy number.

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

It is a de Polignac number, because none of the positive numbers 2^k-91173989 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 (91173983) 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, 21152 + ... + 25094.

It is an arithmetic number, because the mean of its divisors is an integer number (12009480).

Almost surely, 2^91173989 is an apocalyptic number.

It is an amenable number.

91173989 is a deficient number, since it is larger than the sum of its proper divisors (4901851).

91173989 is a wasteful number, since it uses less digits than its factorization.

91173989 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 5179.

The product of its digits is 122472, while the sum is 47.

The square root of 91173989 is about 9548.5071608079. The cubic root of 91173989 is about 450.0806258827.

The spelling of 91173989 in words is "ninety-one million, one hundred seventy-three thousand, nine hundred eighty-nine".