669869 has 2 divisors, whose sum is σ = 669870. Its totient is φ = 669868.

The previous prime is 669863. The next prime is 669887. The reversal of 669869 is 968966.

669869 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 354025 + 315844 = 595^2 + 562^2 .

It is a cyclic number.

It is not a de Polignac number, because 669869 - 2⁴ = 669853 is a prime.

It is a super-2 number, since 2×669869² = 897448954322, which contains 22 as substring.

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 669869.

It is not a weakly prime, because it can be changed into another prime (669863) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 334934 + 334935.

It is an arithmetic number, because the mean of its divisors is an integer number (334935).

2⁶⁶⁹⁸⁶⁹ is an apocalyptic number.

It is an amenable number.

669869 is a deficient number, since it is larger than the sum of its proper divisors (1).

669869 is an equidigital number, since it uses as much as digits as its factorization.

669869 is an evil number, because the sum of its binary digits is even.

The product of its digits is 139968, while the sum is 44.

The square root of 669869 is about 818.4552522893. The cubic root of 669869 is about 87.4976978986.

The spelling of 669869 in words is "six hundred sixty-nine thousand, eight hundred sixty-nine".