643442364451109 has 2 divisors, whose sum is σ = 643442364451110. Its totient is φ = 643442364451108.

The previous prime is 643442364450989. The next prime is 643442364451157. The reversal of 643442364451109 is 901154463244346.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 511319638814884 + 132122725636225 = 22612378^2 + 11494465^2 .

It is a cyclic number.

It is not a de Polignac number, because 643442364451109 - 2²⁰ = 643442363402533 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (643442334451109) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (19) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 321721182225554 + 321721182225555.

It is an arithmetic number, because the mean of its divisors is an integer number (321721182225555).

Almost surely, 2^{643442364451109} is an apocalyptic number.

It is an amenable number.

643442364451109 is a deficient number, since it is larger than the sum of its proper divisors (1).

643442364451109 is an equidigital number, since it uses as much as digits as its factorization.

643442364451109 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 29859840, while the sum is 56.

The spelling of 643442364451109 in words is "six hundred forty-three trillion, four hundred forty-two billion, three hundred sixty-four million, four hundred fifty-one thousand, one hundred nine".