1680681 has 4 divisors (see below), whose sum is σ = 2240912. Its totient is φ = 1120452.

The previous prime is 1680659. The next prime is 1680689. The reversal of 1680681 is 1860861.

1680681 is nontrivially palindromic in base 9.

It is a semiprime because it is the product of two primes, and also a Blum integer, because the two primes are equal to 3 mod 4.

It is not a de Polignac number, because 1680681 - 2⁶ = 1680617 is a prime.

It is a super-2 number, since 2×1680681² = 5649377247522, which contains 22 as substring.

It is a D-number.

It is a Duffinian number.

It is a Curzon number.

It is not an unprimeable number, because it can be changed into a prime (1680689) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 280111 + ... + 280116.

It is an arithmetic number, because the mean of its divisors is an integer number (560228).

2^1680681 is an apocalyptic number.

It is an amenable number.

1680681 is a deficient number, since it is larger than the sum of its proper divisors (560231).

1680681 is an equidigital number, since it uses as much as digits as its factorization.

1680681 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 560230.

The product of its (nonzero) digits is 2304, while the sum is 30.

The square root of 1680681 is about 1296.4108145183. The cubic root of 1680681 is about 118.8944996268.

The spelling of 1680681 in words is "one million, six hundred eighty thousand, six hundred eighty-one".