171391 has 4 divisors (see below), whose sum is σ = 186984. Its totient is φ = 155800.

The previous prime is 171383. The next prime is 171401. The reversal of 171391 is 193171.

171391 = T₁₇₁ + T₁₇₂ + ... + T₁₈₁.

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 171391 - 2³ = 171383 is a prime.

It is a Smith number, since the sum of its digits (22) coincides with the sum of the digits of its prime factors. Since it is squarefree, it is also a hoax number.

It is a Duffinian number.

171391 is a lucky number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (171341) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 7780 + ... + 7801.

It is an arithmetic number, because the mean of its divisors is an integer number (46746).

2¹⁷¹³⁹¹ is an apocalyptic number.

171391 is a gapful number since it is divisible by the number (11) formed by its first and last digit.

171391 is a deficient number, since it is larger than the sum of its proper divisors (15593).

171391 is a wasteful number, since it uses less digits than its factorization.

171391 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 15592.

The product of its digits is 189, while the sum is 22.

The square root of 171391 is about 413.9939613086. The cubic root of 171391 is about 55.5472637995.

The spelling of 171391 in words is "one hundred seventy-one thousand, three hundred ninety-one".