99172591 has 4 divisors (see below), whose sum is σ = 113340112. Its totient is φ = 85005072.

The previous prime is 99172561. The next prime is 99172597. The reversal of 99172591 is 19527199.

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

It is a cyclic number.

It is not a de Polignac number, because 99172591 - 2²³ = 90783983 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 (99172597) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 7083750 + ... + 7083763.

It is an arithmetic number, because the mean of its divisors is an integer number (28335028).

Almost surely, 2^99172591 is an apocalyptic number.

99172591 is a deficient number, since it is larger than the sum of its proper divisors (14167521).

99172591 is a wasteful number, since it uses less digits than its factorization.

99172591 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 14167520.

The product of its digits is 51030, while the sum is 43.

The square root of 99172591 is about 9958.5436184213. The cubic root of 99172591 is about 462.8751721853.

The spelling of 99172591 in words is "ninety-nine million, one hundred seventy-two thousand, five hundred ninety-one".