643776677329 has 2 divisors, whose sum is σ = 643776677330. Its totient is φ = 643776677328.

The previous prime is 643776677303. The next prime is 643776677351. The reversal of 643776677329 is 923776677346.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 638624739600 + 5151937729 = 799140^2 + 71777^2 .

It is a cyclic number.

It is not a de Polignac number, because 643776677329 - 2²¹ = 643774580177 is a prime.

It is not a weakly prime, because it can be changed into another prime (643776677629) 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, 321888338664 + 321888338665.

It is an arithmetic number, because the mean of its divisors is an integer number (321888338665).

Almost surely, 2^643776677329 is an apocalyptic number.

It is an amenable number.

643776677329 is a deficient number, since it is larger than the sum of its proper divisors (1).

643776677329 is an equidigital number, since it uses as much as digits as its factorization.

643776677329 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 336063168, while the sum is 67.

The spelling of 643776677329 in words is "six hundred forty-three billion, seven hundred seventy-six million, six hundred seventy-seven thousand, three hundred twenty-nine".