669680 has 40 divisors (see below), whose sum is σ = 1700784. Its totient is φ = 243200.

The previous prime is 669679. The next prime is 669689. The reversal of 669680 is 86966.

It is a tau number, because it is divible by the number of its divisors (40).

It is a self number, because there is not a number n which added to its sum of digits gives 669680.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (669689) by changing a digit.

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, 500 + ... + 1260.

2⁶⁶⁹⁶⁸⁰ is an apocalyptic number.

It is an amenable number.

It is a practical number, because each smaller number is the sum of distinct divisors of 669680, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (850392).

669680 is an abundant number, since it is smaller than the sum of its proper divisors (1031104).

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

669680 is a wasteful number, since it uses less digits than its factorization.

669680 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 785 (or 779 counting only the distinct ones).

The product of its (nonzero) digits is 15552, while the sum is 35.

The square root of 669680 is about 818.3397827309. The cubic root of 669680 is about 87.4894681201.

It can be divided in two parts, 6696 and 80, that added together give a palindrome (6776).

The spelling of 669680 in words is "six hundred sixty-nine thousand, six hundred eighty".