669905 has 4 divisors (see below), whose sum is σ = 803892. Its totient is φ = 535920.

The previous prime is 669901. The next prime is 669913. The reversal of 669905 is 509966.

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

It can be written as a sum of positive squares in 2 ways, for example, as 528529 + 141376 = 727^2 + 376^2 .

It is not a de Polignac number, because 669905 - 2² = 669901 is a prime.

It is a Duffinian number.

It is an inconsummate number, since it does not exist a number n which divided by its sum of digits gives 669905.

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, 66986 + ... + 66995.

It is an arithmetic number, because the mean of its divisors is an integer number (200973).

2⁶⁶⁹⁹⁰⁵ is an apocalyptic number.

It is an amenable number.

669905 is a deficient number, since it is larger than the sum of its proper divisors (133987).

669905 is a wasteful number, since it uses less digits than its factorization.

669905 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 133986.

The product of its (nonzero) digits is 14580, while the sum is 35.

The square root of 669905 is about 818.4772446440. The cubic root of 669905 is about 87.4992653000.

The spelling of 669905 in words is "six hundred sixty-nine thousand, nine hundred five".