669906 has 12 divisors (see below), whose sum is σ = 1451502. Its totient is φ = 223296.

The previous prime is 669901. The next prime is 669913. The reversal of 669906 is 609966.

It can be written as a sum of positive squares in only one way, i.e., 585225 + 84681 = 765^2 + 291^2 .

It is a Curzon number.

It is an inconsummate number, since it does not exist a number n which divided by its sum of digits gives 669906.

It is not an unprimeable number, because it can be changed into a prime (669901) by changing a digit.

669906 is an untouchable number, because it is not equal to the sum of proper divisors of any number.

It is a polite number, since it can be written in 5 ways as a sum of consecutive naturals, for example, 18591 + ... + 18626.

2⁶⁶⁹⁹⁰⁶ is an apocalyptic number.

669906 is an abundant number, since it is smaller than the sum of its proper divisors (781596).

It is a pseudoperfect number, because it is the sum of a subset of its proper divisors.

669906 is a wasteful number, since it uses less digits than its factorization.

669906 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 37225 (or 37222 counting only the distinct ones).

The product of its (nonzero) digits is 17496, while the sum is 36.

The square root of 669906 is about 818.4778555343. The cubic root of 669906 is about 87.4993088381.

It can be divided in two parts, 66 and 9906, that multiplied together give a triangular number (653796 = T₁₁₄₃).

The spelling of 669906 in words is "six hundred sixty-nine thousand, nine hundred six".