643428888857 has 2 divisors, whose sum is σ = 643428888858. Its totient is φ = 643428888856.

The previous prime is 643428888829. The next prime is 643428888923. The reversal of 643428888857 is 758888824346.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 356672922841 + 286755966016 = 597221^2 + 535496^2 .

It is a cyclic number.

It is not a de Polignac number, because 643428888857 - 2¹⁴ = 643428872473 is a prime.

It is not a weakly prime, because it can be changed into another prime (643428888257) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 321714444428 + 321714444429.

It is an arithmetic number, because the mean of its divisors is an integer number (321714444429).

Almost surely, 2^643428888857 is an apocalyptic number.

It is an amenable number.

643428888857 is a deficient number, since it is larger than the sum of its proper divisors (1).

643428888857 is an equidigital number, since it uses as much as digits as its factorization.

643428888857 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 660602880, while the sum is 71.

The spelling of 643428888857 in words is "six hundred forty-three billion, four hundred twenty-eight million, eight hundred eighty-eight thousand, eight hundred fifty-seven".