1680281 has 4 divisors (see below), whose sum is σ = 1725732. Its totient is φ = 1634832.

The previous prime is 1680277. The next prime is 1680313. The reversal of 1680281 is 1820861.

It is a semiprime because it is the product of two primes.

It can be written as a sum of positive squares in 2 ways, for example, as 648025 + 1032256 = 805^2 + 1016^2 .

It is a cyclic number.

It is not a de Polignac number, because 1680281 - 2² = 1680277 is a prime.

It is a super-2 number, since 2×1680281² = 5646688477922, which contains 22 as substring.

It is a Duffinian number.

It is a Curzon number.

It is a self number, because there is not a number n which added to its sum of digits gives 1680281.

It is not an unprimeable number, because it can be changed into a prime (1680271) 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, 22670 + ... + 22743.

It is an arithmetic number, because the mean of its divisors is an integer number (431433).

2^1680281 is an apocalyptic number.

It is an amenable number.

1680281 is a deficient number, since it is larger than the sum of its proper divisors (45451).

1680281 is an equidigital number, since it uses as much as digits as its factorization.

1680281 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 45450.

The product of its (nonzero) digits is 768, while the sum is 26.

The square root of 1680281 is about 1296.2565332526. The cubic root of 1680281 is about 118.8850666305.

The spelling of 1680281 in words is "one million, six hundred eighty thousand, two hundred eighty-one".