669642 has 16 divisors (see below), whose sum is σ = 1347840. Its totient is φ = 221792.

The previous prime is 669637. The next prime is 669649. The reversal of 669642 is 246966.

It is a Smith number, since the sum of its digits (33) coincides with the sum of the digits of its prime factors. Since it is squarefree, it is also a hoax number.

It is not an unprimeable number, because it can be changed into a prime (669649) by changing a digit.

669642 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 7 ways as a sum of consecutive naturals, for example, 1159 + ... + 1637.

It is an arithmetic number, because the mean of its divisors is an integer number (84240).

2⁶⁶⁹⁶⁴² is an apocalyptic number.

669642 is an abundant number, since it is smaller than the sum of its proper divisors (678198).

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

669642 is a wasteful number, since it uses less digits than its factorization.

669642 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 717.

The product of its digits is 15552, while the sum is 33.

The square root of 669642 is about 818.3165646619. The cubic root of 669642 is about 87.4878132687.

It can be divided in two parts, 66964 and 2, that added together give a palindrome (66966).

The spelling of 669642 in words is "six hundred sixty-nine thousand, six hundred forty-two".