171840 has 56 divisors (see below), whose sum is σ = 548640. Its totient is φ = 45568.

The previous prime is 171827. The next prime is 171851. The reversal of 171840 is 48171.

It is a congruent number.

It is an unprimeable number.

171840 is an untouchable number, because it is not equal to the sum of proper divisors of any number.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 871 + ... + 1049.

2¹⁷¹⁸⁴⁰ is an apocalyptic number.

171840 is a gapful number since it is divisible by the number (10) formed by its first and last digit.

It is an amenable number.

It is a practical number, because each smaller number is the sum of distinct divisors of 171840, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (274320).

171840 is an abundant number, since it is smaller than the sum of its proper divisors (376800).

It is a pseudoperfect number, because it is the sum of a subset of its proper divisors.

171840 is a wasteful number, since it uses less digits than its factorization.

171840 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 199 (or 189 counting only the distinct ones).

The product of its (nonzero) digits is 224, while the sum is 21.

The square root of 171840 is about 414.5358850570. The cubic root of 171840 is about 55.5957279812.

The spelling of 171840 in words is "one hundred seventy-one thousand, eight hundred forty".