171921 has 8 divisors (see below), whose sum is σ = 242784. Its totient is φ = 107840.

The previous prime is 171917. The next prime is 171923. The reversal of 171921 is 129171.

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 171921 - 2² = 171917 is a prime.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (171923) 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, 1635 + ... + 1736.

It is an arithmetic number, because the mean of its divisors is an integer number (30348).

2¹⁷¹⁹²¹ is an apocalyptic number.

It is an amenable number.

171921 is a deficient number, since it is larger than the sum of its proper divisors (70863).

171921 is a wasteful number, since it uses less digits than its factorization.

171921 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 3391.

The product of its digits is 126, while the sum is 21.

The square root of 171921 is about 414.6335731703. The cubic root of 171921 is about 55.6044619713.

The spelling of 171921 in words is "one hundred seventy-one thousand, nine hundred twenty-one".