1680321 has 4 divisors (see below), whose sum is σ = 2240432. Its totient is φ = 1120212.

The previous prime is 1680319. The next prime is 1680323. The reversal of 1680321 is 1230861.

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 an interprime number because it is at equal distance from previous prime (1680319) and next prime (1680323).

It is not a de Polignac number, because 1680321 - 2¹ = 1680319 is a prime.

It is a D-number.

It is a Duffinian number.

1680321 is a lucky number.

It is not an unprimeable number, because it can be changed into a prime (1680323) 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, 280051 + ... + 280056.

It is an arithmetic number, because the mean of its divisors is an integer number (560108).

2^1680321 is an apocalyptic number.

It is an amenable number.

1680321 is a deficient number, since it is larger than the sum of its proper divisors (560111).

1680321 is an equidigital number, since it uses as much as digits as its factorization.

1680321 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 560110.

The product of its (nonzero) digits is 288, while the sum is 21.

The square root of 1680321 is about 1296.2719622055. The cubic root of 1680321 is about 118.8860099975.

The spelling of 1680321 in words is "one million, six hundred eighty thousand, three hundred twenty-one".