170891 has 4 divisors (see below), whose sum is σ = 195312. Its totient is φ = 146472.

The previous prime is 170887. The next prime is 170899. The reversal of 170891 is 198071.

It is a semiprime because it is the product of two primes, and also an emirpimes, since its reverse is a distinct semiprime: 198071 = 41 ⋅4831.

It is a cyclic number.

It is not a de Polignac number, because 170891 - 2² = 170887 is a prime.

It is an Ulam number.

It is a Duffinian number.

It is a self number, because there is not a number n which added to its sum of digits gives 170891.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (170899) 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, 12200 + ... + 12213.

It is an arithmetic number, because the mean of its divisors is an integer number (48828).

2¹⁷⁰⁸⁹¹ is an apocalyptic number.

170891 is a deficient number, since it is larger than the sum of its proper divisors (24421).

170891 is an equidigital number, since it uses as much as digits as its factorization.

170891 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 24420.

The product of its (nonzero) digits is 504, while the sum is 26.

The square root of 170891 is about 413.3896467015. The cubic root of 170891 is about 55.4931950643.

The spelling of 170891 in words is "one hundred seventy thousand, eight hundred ninety-one".