1681904 has 20 divisors (see below), whose sum is σ = 3724464. Its totient is φ = 720768.

The previous prime is 1681903. The next prime is 1681907. The reversal of 1681904 is 4091861.

It is a Smith number, since the sum of its digits (29) coincides with the sum of the digits of its prime factors.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (1681903) 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 3 ways as a sum of consecutive naturals, for example, 7397 + ... + 7620.

2^1681904 is an apocalyptic number.

1681904 is a gapful number since it is divisible by the number (14) formed by its first and last digit.

It is an amenable number.

1681904 is an abundant number, since it is smaller than the sum of its proper divisors (2042560).

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

1681904 is a wasteful number, since it uses less digits than its factorization.

1681904 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 15032 (or 15026 counting only the distinct ones).

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

The square root of 1681904 is about 1296.8824156414. The cubic root of 1681904 is about 118.9233317326.

The spelling of 1681904 in words is "one million, six hundred eighty-one thousand, nine hundred four".