1680640 has 72 divisors (see below), whose sum is σ = 4378248. Its totient is φ = 614400.

The previous prime is 1680617. The next prime is 1680643. The reversal of 1680640 is 460861.

It can be written as a sum of positive squares in 4 ways, for example, as 278784 + 1401856 = 528^2 + 1184^2 .

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (1680643) by changing a digit.

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, 16590 + ... + 16690.

It is an arithmetic number, because the mean of its divisors is an integer number (60809).

2^1680640 is an apocalyptic number.

1680640 is a gapful number since it is divisible by the number (10) 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 1680640, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (2189124).

1680640 is an abundant number, since it is smaller than the sum of its proper divisors (2697608).

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

1680640 is a wasteful number, since it uses less digits than its factorization.

1680640 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 135 (or 121 counting only the distinct ones).

The product of its (nonzero) digits is 1152, while the sum is 25.

The square root of 1680640 is about 1296.3950015331. The cubic root of 1680640 is about 118.8935328136.

It can be divided in two parts, 16 and 80640, that added together give a square (80656 = 284²).

The spelling of 1680640 in words is "one million, six hundred eighty thousand, six hundred forty".