669689 has 2 divisors, whose sum is σ = 669690.
Its totient is φ = 669688.
The previous prime is 669679. The next prime is 669701. The reversal of 669689 is 986966.
It is a weak prime.
It can be written as a sum of positive squares in only one way, i.e., 350464 + 319225 = 592^2 + 565^2
It is a cyclic number.
It is not a de Polignac number, because 669689 - 24 = 669673 is a prime.
It is not a weakly prime, because it can be changed into another prime (669649) by changing a digit.
It is a pernicious number, because its binary representation contains a prime number (13) of ones.
It is a polite number, since it can be written as a sum of consecutive naturals, namely, 334844 + 334845.
It is an arithmetic number, because the mean of its divisors is an integer number (334845).
2669689 is an apocalyptic number.
It is an amenable number.
669689 is a deficient number, since it is larger than the sum of its proper divisors (1).
669689 is an equidigital number, since it uses as much as digits as its factorization.
669689 is an odious number, because the sum of its binary digits is odd.
The product of its digits is 139968, while the sum is 44.
The square root of 669689 is about 818.3452816507.
The cubic root of 669689 is about 87.4898600495.
The spelling of 669689 in words is "six hundred sixty-nine thousand, six hundred eighty-nine".