669942 has 48 divisors (see below), whose sum is σ = 1790880. Its totient is φ = 176256.

The previous prime is 669937. The next prime is 669943. The reversal of 669942 is 249966.

It is a junction number, because it is equal to n+sod(n) for n = 669897 and 669906.

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 669942.

It is not an unprimeable number, because it can be changed into a prime (669943) by changing a digit.

669942 is an untouchable number, because it is not equal to the sum of proper divisors of any number.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written in 23 ways as a sum of consecutive naturals, for example, 1434 + ... + 1842.

It is an arithmetic number, because the mean of its divisors is an integer number (37310).

2⁶⁶⁹⁹⁴² is an apocalyptic number.

It is a pronic number, being equal to 818×819.

It is a practical number, because each smaller number is the sum of distinct divisors of 669942, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (895440).

669942 is an abundant number, since it is smaller than the sum of its proper divisors (1120938).

It is a pseudoperfect number, because it is the sum of a subset of its proper divisors.

669942 is a wasteful number, since it uses less digits than its factorization.

669942 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 437 (or 434 counting only the distinct ones).

The product of its digits is 23328, while the sum is 36.

The square root of 669942 is about 818.4998472816. The cubic root of 669942 is about 87.5008761817.

The spelling of 669942 in words is "six hundred sixty-nine thousand, nine hundred forty-two".