647321 has 2 divisors, whose sum is σ = 647322. Its totient is φ = 647320.

The previous prime is 647303. The next prime is 647327. The reversal of 647321 is 123746.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 541696 + 105625 = 736^2 + 325^2 .

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-647321 is a prime.

It is a Chen prime.

It is an inconsummate number, since it does not exist a number n which divided by its sum of digits gives 647321.

It is not a weakly prime, because it can be changed into another prime (647327) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 323660 + 323661.

It is an arithmetic number, because the mean of its divisors is an integer number (323661).

2⁶⁴⁷³²¹ is an apocalyptic number.

It is an amenable number.

647321 is a deficient number, since it is larger than the sum of its proper divisors (1).

647321 is an equidigital number, since it uses as much as digits as its factorization.

647321 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 1008, while the sum is 23.

The square root of 647321 is about 804.5626140954. The cubic root of 647321 is about 86.5047387338.

The spelling of 647321 in words is "six hundred forty-seven thousand, three hundred twenty-one".