643259972101 has 2 divisors, whose sum is σ = 643259972102. Its totient is φ = 643259972100.

The previous prime is 643259972093. The next prime is 643259972119. The reversal of 643259972101 is 101279952346.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 444855650625 + 198404321476 = 666975^2 + 445426^2 .

It is a cyclic number.

It is not a de Polignac number, because 643259972101 - 2³ = 643259972093 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (643259972141) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 321629986050 + 321629986051.

It is an arithmetic number, because the mean of its divisors is an integer number (321629986051).

Almost surely, 2^643259972101 is an apocalyptic number.

It is an amenable number.

643259972101 is a deficient number, since it is larger than the sum of its proper divisors (1).

643259972101 is an equidigital number, since it uses as much as digits as its factorization.

643259972101 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 816480, while the sum is 49.

The spelling of 643259972101 in words is "six hundred forty-three billion, two hundred fifty-nine million, nine hundred seventy-two thousand, one hundred one".