166861 has 2 divisors, whose sum is σ = 166862. Its totient is φ = 166860.

The previous prime is 166853. The next prime is 166867. The reversal of 166861 is 168661.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 164836 + 2025 = 406^2 + 45^2 .

It is a cyclic number.

It is not a de Polignac number, because 166861 - 2³ = 166853 is a prime.

It is a Chen prime.

It is a plaindrome in base 16.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (166867) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 83430 + 83431.

It is an arithmetic number, because the mean of its divisors is an integer number (83431).

2¹⁶⁶⁸⁶¹ is an apocalyptic number.

It is an amenable number.

166861 is a deficient number, since it is larger than the sum of its proper divisors (1).

166861 is an equidigital number, since it uses as much as digits as its factorization.

166861 is an evil number, because the sum of its binary digits is even.

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

The square root of 166861 is about 408.4862298781. The cubic root of 166861 is about 55.0535016580.

The spelling of 166861 in words is "one hundred sixty-six thousand, eight hundred sixty-one".