643788138241 has 2 divisors, whose sum is σ = 643788138242. Its totient is φ = 643788138240.

The previous prime is 643788138221. The next prime is 643788138251. The reversal of 643788138241 is 142831887346.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 597535184016 + 46252954225 = 773004^2 + 215065^2 .

It is a cyclic number.

It is not a de Polignac number, because 643788138241 - 2⁵ = 643788138209 is a prime.

It is not a weakly prime, because it can be changed into another prime (643788138221) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 321894069120 + 321894069121.

It is an arithmetic number, because the mean of its divisors is an integer number (321894069121).

Almost surely, 2^643788138241 is an apocalyptic number.

It is an amenable number.

643788138241 is a deficient number, since it is larger than the sum of its proper divisors (1).

643788138241 is an equidigital number, since it uses as much as digits as its factorization.

643788138241 is an evil number, because the sum of its binary digits is even.

The product of its digits is 6193152, while the sum is 55.

The spelling of 643788138241 in words is "six hundred forty-three billion, seven hundred eighty-eight million, one hundred thirty-eight thousand, two hundred forty-one".