1681940 has 24 divisors (see below), whose sum is σ = 3804360. Its totient is φ = 620928.

The previous prime is 1681931. The next prime is 1681957. The reversal of 1681940 is 491861.

It can be written as a sum of positive squares in 4 ways, for example, as 38416 + 1643524 = 196^2 + 1282^2 .

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, 2975 + ... + 3494.

It is an arithmetic number, because the mean of its divisors is an integer number (158515).

2^1681940 is an apocalyptic number.

1681940 is a gapful number since it is divisible by the number (10) formed by its first and last digit.

It is an amenable number.

1681940 is an abundant number, since it is smaller than the sum of its proper divisors (2122420).

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

1681940 is a wasteful number, since it uses less digits than its factorization.

1681940 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 6491 (or 6489 counting only the distinct ones).

The product of its (nonzero) digits is 1728, while the sum is 29.

The square root of 1681940 is about 1296.8962950059. The cubic root of 1681940 is about 118.9241802173.

The spelling of 1681940 in words is "one million, six hundred eighty-one thousand, nine hundred forty".