669679 has 2 divisors, whose sum is σ = 669680. Its totient is φ = 669678.

The previous prime is 669677. The next prime is 669689. The reversal of 669679 is 976966.

It is a happy number.

It is a weak prime.

It is a cyclic number.

It is not a de Polignac number, because 669679 - 2¹ = 669677 is a prime.

Together with 669677, it forms a pair of twin primes.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (669673) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 334839 + 334840.

It is an arithmetic number, because the mean of its divisors is an integer number (334840).

2⁶⁶⁹⁶⁷⁹ is an apocalyptic number.

669679 is a deficient number, since it is larger than the sum of its proper divisors (1).

669679 is an equidigital number, since it uses as much as digits as its factorization.

669679 is an evil number, because the sum of its binary digits is even.

The product of its digits is 122472, while the sum is 43.

The square root of 669679 is about 818.3391717375. The cubic root of 669679 is about 87.4894245722.

The spelling of 669679 in words is "six hundred sixty-nine thousand, six hundred seventy-nine".