6391321 has 2 divisors, whose sum is σ = 6391322. Its totient is φ = 6391320.

The previous prime is 6391289. The next prime is 6391327. The reversal of 6391321 is 1231936.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 5125696 + 1265625 = 2264^2 + 1125^2 .

It is a cyclic number.

It is not a de Polignac number, because 6391321 - 2⁵ = 6391289 is a prime.

It is not a weakly prime, because it can be changed into another prime (6391327) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 3195660 + 3195661.

It is an arithmetic number, because the mean of its divisors is an integer number (3195661).

Almost surely, 2^6391321 is an apocalyptic number.

It is an amenable number.

6391321 is a deficient number, since it is larger than the sum of its proper divisors (1).

6391321 is an equidigital number, since it uses as much as digits as its factorization.

6391321 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 972, while the sum is 25.

The square root of 6391321 is about 2528.1062082120. The cubic root of 6391321 is about 185.5795896508.

The spelling of 6391321 in words is "six million, three hundred ninety-one thousand, three hundred twenty-one".