669943 has 2 divisors, whose sum is σ = 669944. Its totient is φ = 669942.

The previous prime is 669937. The next prime is 669947. The reversal of 669943 is 349966.

It is a strong prime.

It is a cyclic number.

It is not a de Polignac number, because 669943 - 2¹⁷ = 538871 is a prime.

It is the 819-th Hogben number.

669943 is a lucky number.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (669947) by changing a digit.

It is a nontrivial repunit in base 818.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 334971 + 334972.

It is an arithmetic number, because the mean of its divisors is an integer number (334972).

2⁶⁶⁹⁹⁴³ is an apocalyptic number.

669943 is a deficient number, since it is larger than the sum of its proper divisors (1).

669943 is an equidigital number, since it uses as much as digits as its factorization.

669943 is an evil number, because the sum of its binary digits is even.

The product of its digits is 34992, while the sum is 37.

The square root of 669943 is about 818.5004581550. The cubic root of 669943 is about 87.5009197182.

The spelling of 669943 in words is "six hundred sixty-nine thousand, nine hundred forty-three".