171661 has 8 divisors (see below), whose sum is σ = 198720. Its totient is φ = 145248.

The previous prime is 171659. The next prime is 171671. The reversal of 171661 is 166171.

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 171661 - 2¹ = 171659 is a prime.

It is a super-3 number, since 3×171661³ = 15175260996833343, which contains 333 as substring.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (171641) 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, 870 + ... + 1048.

It is an arithmetic number, because the mean of its divisors is an integer number (24840).

2¹⁷¹⁶⁶¹ is an apocalyptic number.

It is an amenable number.

171661 is a deficient number, since it is larger than the sum of its proper divisors (27059).

171661 is a wasteful number, since it uses less digits than its factorization.

171661 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 323.

The product of its digits is 252, while the sum is 22.

The square root of 171661 is about 414.3199246959. The cubic root of 171661 is about 55.5764172023.

The spelling of 171661 in words is "one hundred seventy-one thousand, six hundred sixty-one".