1680440 has 32 divisors (see below), whose sum is σ = 3872880. Its totient is φ = 655872.

The previous prime is 1680439. The next prime is 1680457. The reversal of 1680440 is 440861.

It is a happy number.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 1232 + ... + 2208.

2^1680440 is an apocalyptic number.

1680440 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 1680440, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (1936440).

1680440 is an abundant number, since it is smaller than the sum of its proper divisors (2192440).

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

1680440 is a wasteful number, since it uses less digits than its factorization.

1680440 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1031 (or 1027 counting only the distinct ones).

The product of its (nonzero) digits is 768, while the sum is 23.

The square root of 1680440 is about 1296.3178622545. The cubic root of 1680440 is about 118.8888164258. Note that the first 4 decimals are identical.

The spelling of 1680440 in words is "one million, six hundred eighty thousand, four hundred forty".