172191 has 4 divisors (see below), whose sum is σ = 229592. Its totient is φ = 114792.

The previous prime is 172181. The next prime is 172199. The reversal of 172191 is 191271.

172191 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.

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

It is not a de Polignac number, because 172191 - 2⁶ = 172127 is a prime.

It is a D-number.

It is a Duffinian number.

172191 is a lucky number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (172199) 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, 28696 + ... + 28701.

It is an arithmetic number, because the mean of its divisors is an integer number (57398).

2¹⁷²¹⁹¹ is an apocalyptic number.

172191 is a deficient number, since it is larger than the sum of its proper divisors (57401).

172191 is an equidigital number, since it uses as much as digits as its factorization.

172191 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 57400.

The product of its digits is 126, while the sum is 21.

The square root of 172191 is about 414.9590341226. The cubic root of 172191 is about 55.6335554740.

It can be divided in two parts, 172 and 191, that added together give a palindrome (363).

The spelling of 172191 in words is "one hundred seventy-two thousand, one hundred ninety-one".