2166999 has 4 divisors (see below), whose sum is σ = 2889336. Its totient is φ = 1444664.

The previous prime is 2166977. The next prime is 2167003. The reversal of 2166999 is 9996612.

It is a happy number.

It is a semiprime because it is the product of two primes.

It is a cyclic number.

It is not a de Polignac number, because 2166999 - 2¹⁷ = 2035927 is a prime.

It is a D-number.

2166999 is a lucky number.

It is a self number, because there is not a number n which added to its sum of digits gives 2166999.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (2166919) 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, 361164 + ... + 361169.

It is an arithmetic number, because the mean of its divisors is an integer number (722334).

2^2166999 is an apocalyptic number.

2166999 is a deficient number, since it is larger than the sum of its proper divisors (722337).

2166999 is an equidigital number, since it uses as much as digits as its factorization.

2166999 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 722336.

The product of its digits is 52488, while the sum is 42.

The square root of 2166999 is about 1472.0730280798. The cubic root of 2166999 is about 129.4055502080.

The spelling of 2166999 in words is "two million, one hundred sixty-six thousand, nine hundred ninety-nine".