172861 has 4 divisors (see below), whose sum is σ = 186172. Its totient is φ = 159552.

The previous prime is 172859. The next prime is 172867. The reversal of 172861 is 168271.

It is a semiprime because it is the product of two primes, and also an emirpimes, since its reverse is a distinct semiprime: 168271 = 191 ⋅881.

It can be written as a sum of positive squares in 2 ways, for example, as 8836 + 164025 = 94^2 + 405^2 .

It is a cyclic number.

It is not a de Polignac number, because 172861 - 2¹ = 172859 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 (172867) 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, 6636 + ... + 6661.

It is an arithmetic number, because the mean of its divisors is an integer number (46543).

2¹⁷²⁸⁶¹ is an apocalyptic number.

It is an amenable number.

172861 is a deficient number, since it is larger than the sum of its proper divisors (13311).

172861 is a wasteful number, since it uses less digits than its factorization.

172861 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 13310.

The product of its digits is 672, while the sum is 25.

The square root of 172861 is about 415.7655589392. The cubic root of 172861 is about 55.7056193276.

The spelling of 172861 in words is "one hundred seventy-two thousand, eight hundred sixty-one".