168661 has 4 divisors (see below), whose sum is σ = 169632. Its totient is φ = 167692.

The previous prime is 168643. The next prime is 168673. The reversal of 168661 is 166861.

168661 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.

It is a semiprime because it is the product of two primes, and also a Blum integer, because the two primes are equal to 3 mod 4, and also a brilliant number, because the two primes have the same length.

It is a cyclic number.

It is not a de Polignac number, because 168661 - 2⁵ = 168629 is a prime.

It is a Duffinian number.

168661 is a lucky number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (168601) 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, 145 + ... + 598.

It is an arithmetic number, because the mean of its divisors is an integer number (42408).

2¹⁶⁸⁶⁶¹ is an apocalyptic number.

It is an amenable number.

168661 is a deficient number, since it is larger than the sum of its proper divisors (971).

168661 is an equidigital number, since it uses as much as digits as its factorization.

168661 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 970.

The product of its digits is 1728, while the sum is 28.

The square root of 168661 is about 410.6835764917. The cubic root of 168661 is about 55.2507558437.

The spelling of 168661 in words is "one hundred sixty-eight thousand, six hundred sixty-one".