644357215522193 has 2 divisors, whose sum is σ = 644357215522194. Its totient is φ = 644357215522192.

The previous prime is 644357215522177. The next prime is 644357215522283. The reversal of 644357215522193 is 391225512753446.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 644306233043344 + 50982478849 = 25383188^2 + 225793^2 .

It is a cyclic number.

It is not a de Polignac number, because 644357215522193 - 2⁴ = 644357215522177 is a prime.

It is not a weakly prime, because it can be changed into another prime (644357215522103) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 322178607761096 + 322178607761097.

It is an arithmetic number, because the mean of its divisors is an integer number (322178607761097).

Almost surely, 2^{644357215522193} is an apocalyptic number.

It is an amenable number.

644357215522193 is a deficient number, since it is larger than the sum of its proper divisors (1).

644357215522193 is an equidigital number, since it uses as much as digits as its factorization.

644357215522193 is an evil number, because the sum of its binary digits is even.

The product of its digits is 54432000, while the sum is 59.

The spelling of 644357215522193 in words is "six hundred forty-four trillion, three hundred fifty-seven billion, two hundred fifteen million, five hundred twenty-two thousand, one hundred ninety-three".