680640 has 56 divisors (see below), whose sum is σ = 2164080. Its totient is φ = 181248.

The previous prime is 680633. The next prime is 680651. The reversal of 680640 is 46086.

It is a Harshad number since it is a multiple of its sum of digits (24).

It is a self number, because there is not a number n which added to its sum of digits gives 680640.

It is a congruent number.

It is an unprimeable number.

680640 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 (7) of ones.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 606 + ... + 1314.

2⁶⁸⁰⁶⁴⁰ is an apocalyptic number.

680640 is a gapful number since it is divisible by the number (60) formed by its first and last digit.

It is an amenable number.

It is a practical number, because each smaller number is the sum of distinct divisors of 680640, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (1082040).

680640 is an abundant number, since it is smaller than the sum of its proper divisors (1483440).

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

680640 is a wasteful number, since it uses less digits than its factorization.

680640 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 729 (or 719 counting only the distinct ones).

The product of its (nonzero) digits is 1152, while the sum is 24.

The square root of 680640 is about 825.0090908590. The cubic root of 680640 is about 87.9641727435.

The spelling of 680640 in words is "six hundred eighty thousand, six hundred forty".