669879 has 30 divisors (see below), whose sum is σ = 1165216. Its totient is φ = 370440.

The previous prime is 669869. The next prime is 669887. The reversal of 669879 is 978966.

It is not a de Polignac number, because 669879 - 2⁴ = 669863 is a prime.

It is a Duffinian number.

It is a congruent number.

It is an inconsummate number, since it does not exist a number n which divided by its sum of digits gives 669879.

It is not an unprimeable number, because it can be changed into a prime (669839) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written in 29 ways as a sum of consecutive naturals, for example, 21594 + ... + 21624.

2⁶⁶⁹⁸⁷⁹ is an apocalyptic number.

669879 is a deficient number, since it is larger than the sum of its proper divisors (495337).

669879 is an equidigital number, since it uses as much as digits as its factorization.

669879 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 65 (or 41 counting only the distinct ones).

The product of its digits is 163296, while the sum is 45.

The square root of 669879 is about 818.4613613360. The cubic root of 669879 is about 87.4981332935.

The spelling of 669879 in words is "six hundred sixty-nine thousand, eight hundred seventy-nine".