669909 has 4 divisors (see below), whose sum is σ = 893216. Its totient is φ = 446604.

The previous prime is 669901. The next prime is 669913. The reversal of 669909 is 909966.

669909 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, and also a Blum integer, because the two primes are equal to 3 mod 4.

It is not a de Polignac number, because 669909 - 2³ = 669901 is a prime.

It is a D-number.

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 669909.

It is not an unprimeable number, because it can be changed into a prime (669901) 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, 111649 + ... + 111654.

It is an arithmetic number, because the mean of its divisors is an integer number (223304).

2⁶⁶⁹⁹⁰⁹ is an apocalyptic number.

It is an amenable number.

669909 is a deficient number, since it is larger than the sum of its proper divisors (223307).

669909 is a wasteful number, since it uses less digits than its factorization.

669909 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 223306.

The product of its (nonzero) digits is 26244, while the sum is 39.

The square root of 669909 is about 818.4796882025. The cubic root of 669909 is about 87.4994394522.

The spelling of 669909 in words is "six hundred sixty-nine thousand, nine hundred nine".