644216347 has 2 divisors, whose sum is σ = 644216348. Its totient is φ = 644216346.

The previous prime is 644216317. The next prime is 644216371. The reversal of 644216347 is 743612446.

It is a strong prime.

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-644216347 is a prime.

It is not a weakly prime, because it can be changed into another prime (644216317) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 322108173 + 322108174.

It is an arithmetic number, because the mean of its divisors is an integer number (322108174).

Almost surely, 2^644216347 is an apocalyptic number.

644216347 is a deficient number, since it is larger than the sum of its proper divisors (1).

644216347 is an equidigital number, since it uses as much as digits as its factorization.

644216347 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 96768, while the sum is 37.

The square root of 644216347 is about 25381.4173560107. The cubic root of 644216347 is about 863.6622028220.

The spelling of 644216347 in words is "six hundred forty-four million, two hundred sixteen thousand, three hundred forty-seven".