172391 has 8 divisors (see below), whose sum is σ = 182784. Its totient is φ = 162360.

The previous prime is 172373. The next prime is 172399. The reversal of 172391 is 193271.

172391 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.

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 172391 - 2¹⁴ = 156007 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 (172399) 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, 2036 + ... + 2118.

It is an arithmetic number, because the mean of its divisors is an integer number (22848).

2¹⁷²³⁹¹ is an apocalyptic number.

172391 is a deficient number, since it is larger than the sum of its proper divisors (10393).

172391 is an equidigital number, since it uses as much as digits as its factorization.

172391 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 181.

The product of its digits is 378, while the sum is 23.

The square root of 172391 is about 415.1999518304. The cubic root of 172391 is about 55.6550866148.

The spelling of 172391 in words is "one hundred seventy-two thousand, three hundred ninety-one".