172891 has 4 divisors (see below), whose sum is σ = 180432. Its totient is φ = 165352.

The previous prime is 172883. The next prime is 172933. The reversal of 172891 is 198271.

172891 = T₃₃₈ + T₃₃₉ + T₃₄₀.

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 172891 - 2³ = 172883 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (172801) 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, 3736 + ... + 3781.

It is an arithmetic number, because the mean of its divisors is an integer number (45108).

2¹⁷²⁸⁹¹ is an apocalyptic number.

172891 is the 340-th centered triangular number.

172891 is a deficient number, since it is larger than the sum of its proper divisors (7541).

172891 is an equidigital number, since it uses as much as digits as its factorization.

172891 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 7540.

The product of its digits is 1008, while the sum is 28.

The square root of 172891 is about 415.8016353984. The cubic root of 172891 is about 55.7088417084.

The spelling of 172891 in words is "one hundred seventy-two thousand, eight hundred ninety-one".