647315321 has 2 divisors, whose sum is σ = 647315322. Its totient is φ = 647315320.

The previous prime is 647315303. The next prime is 647315323. The reversal of 647315321 is 123513746.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 597118096 + 50197225 = 24436^2 + 7085^2 .

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-647315321 is a prime.

It is a Sophie Germain prime.

Together with 647315323, it forms a pair of twin primes.

It is a Chen prime.

It is a Curzon number.

It is not a weakly prime, because it can be changed into another prime (647315323) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 323657660 + 323657661.

It is an arithmetic number, because the mean of its divisors is an integer number (323657661).

Almost surely, 2^647315321 is an apocalyptic number.

It is an amenable number.

647315321 is a deficient number, since it is larger than the sum of its proper divisors (1).

647315321 is an equidigital number, since it uses as much as digits as its factorization.

647315321 is an evil number, because the sum of its binary digits is even.

The product of its digits is 15120, while the sum is 32.

The square root of 647315321 is about 25442.3922027784. The cubic root of 647315321 is about 865.0448576200.

The spelling of 647315321 in words is "six hundred forty-seven million, three hundred fifteen thousand, three hundred twenty-one".