647642321 has 2 divisors, whose sum is σ = 647642322. Its totient is φ = 647642320.

The previous prime is 647642311. The next prime is 647642323. The reversal of 647642321 is 123246746.

647642321 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 621006400 + 26635921 = 24920^2 + 5161^2 .

It is a cyclic number.

It is not a de Polignac number, because 647642321 - 2¹⁰ = 647641297 is a prime.

Together with 647642323, it forms a pair of twin primes.

It is a Chen prime.

It is not a weakly prime, because it can be changed into another prime (647642323) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 323821160 + 323821161.

It is an arithmetic number, because the mean of its divisors is an integer number (323821161).

Almost surely, 2^647642321 is an apocalyptic number.

It is an amenable number.

647642321 is a deficient number, since it is larger than the sum of its proper divisors (1).

647642321 is an equidigital number, since it uses as much as digits as its factorization.

647642321 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 48384, while the sum is 35.

The square root of 647642321 is about 25448.8176739117. The cubic root of 647642321 is about 865.1904960958.

The spelling of 647642321 in words is "six hundred forty-seven million, six hundred forty-two thousand, three hundred twenty-one".