166999 has 4 divisors (see below), whose sum is σ = 190864. Its totient is φ = 143136.

The previous prime is 166987. The next prime is 167009. The reversal of 166999 is 999661.

166999 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.

It is not a de Polignac number, because 166999 - 2⁵ = 166967 is a prime.

It is a Duffinian number.

166999 is a modest number, since divided by 999 gives 166 as remainder.

166999 is a lucky number.

It is a plaindrome in base 10.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (166909) 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, 11922 + ... + 11935.

It is an arithmetic number, because the mean of its divisors is an integer number (47716).

2¹⁶⁶⁹⁹⁹ is an apocalyptic number.

166999 is a deficient number, since it is larger than the sum of its proper divisors (23865).

166999 is an equidigital number, since it uses as much as digits as its factorization.

166999 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 23864.

The product of its digits is 26244, while the sum is 40.

The square root of 166999 is about 408.6551113103. The cubic root of 166999 is about 55.0686745459.

The spelling of 166999 in words is "one hundred sixty-six thousand, nine hundred ninety-nine".