2166639 has 4 divisors (see below), whose sum is σ = 2888856. Its totient is φ = 1444424.

The previous prime is 2166629. The next prime is 2166673. The reversal of 2166639 is 9366612.

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 2166639 - 2⁵ = 2166607 is a prime.

It is a D-number.

2166639 is a lucky number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (2166629) 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, 361104 + ... + 361109.

It is an arithmetic number, because the mean of its divisors is an integer number (722214).

2^2166639 is an apocalyptic number.

2166639 is a deficient number, since it is larger than the sum of its proper divisors (722217).

2166639 is an equidigital number, since it uses as much as digits as its factorization.

2166639 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 722216.

The product of its digits is 11664, while the sum is 33.

The square root of 2166639 is about 1471.9507464586. The cubic root of 2166639 is about 129.3983838336.

The spelling of 2166639 in words is "two million, one hundred sixty-six thousand, six hundred thirty-nine".