643576317281 has 2 divisors, whose sum is σ = 643576317282. Its totient is φ = 643576317280.

The previous prime is 643576317233. The next prime is 643576317337. The reversal of 643576317281 is 182713675346.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 329734350625 + 313841966656 = 574225^2 + 560216^2 .

It is a cyclic number.

It is not a de Polignac number, because 643576317281 - 2⁶ = 643576317217 is a prime.

It is a super-2 number, since 2×643576317281² (a number of 24 digits) contains 22 as substring.

It is a Sophie Germain prime.

It is a Curzon number.

It is not a weakly prime, because it can be changed into another prime (643576317211) 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, 321788158640 + 321788158641.

It is an arithmetic number, because the mean of its divisors is an integer number (321788158641).

Almost surely, 2^643576317281 is an apocalyptic number.

It is an amenable number.

643576317281 is a deficient number, since it is larger than the sum of its proper divisors (1).

643576317281 is an equidigital number, since it uses as much as digits as its factorization.

643576317281 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 5080320, while the sum is 53.

The spelling of 643576317281 in words is "six hundred forty-three billion, five hundred seventy-six million, three hundred seventeen thousand, two hundred eighty-one".