669989 has 2 divisors, whose sum is σ = 669990. Its totient is φ = 669988.

The previous prime is 669971. The next prime is 670001. The reversal of 669989 is 989966.

It is a happy number.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 667489 + 2500 = 817^2 + 50^2 .

It is a cyclic number.

It is not a de Polignac number, because 669989 - 2⁸ = 669733 is a prime.

It is a Chen prime.

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 669989.

It is not a weakly prime, because it can be changed into another prime (669089) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 334994 + 334995.

It is an arithmetic number, because the mean of its divisors is an integer number (334995).

2⁶⁶⁹⁹⁸⁹ is an apocalyptic number.

It is an amenable number.

669989 is a deficient number, since it is larger than the sum of its proper divisors (1).

669989 is an equidigital number, since it uses as much as digits as its factorization.

669989 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 209952, while the sum is 47.

The square root of 669989 is about 818.5285578402. The cubic root of 669989 is about 87.5029223514.

The spelling of 669989 in words is "six hundred sixty-nine thousand, nine hundred eighty-nine".