643849259117 has 4 divisors (see below), whose sum is σ = 643852842300. Its totient is φ = 643845675936.

The previous prime is 643849259101. The next prime is 643849259149. The reversal of 643849259117 is 711952948346.

It is a happy number.

It is a semiprime because it is the product of two primes.

It can be written as a sum of positive squares in 2 ways, for example, as 426740788516 + 217108470601 = 653254^2 + 465949^2 .

It is a cyclic number.

It is not a de Polignac number, because 643849259117 - 2⁴ = 643849259101 is a prime.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (643849259167) 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 in 3 ways as a sum of consecutive naturals, for example, 1506992 + ... + 1886457.

It is an arithmetic number, because the mean of its divisors is an integer number (160963210575).

Almost surely, 2^643849259117 is an apocalyptic number.

It is an amenable number.

643849259117 is a deficient number, since it is larger than the sum of its proper divisors (3583183).

643849259117 is a wasteful number, since it uses less digits than its factorization.

643849259117 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 3583182.

The product of its digits is 13063680, while the sum is 59.

The spelling of 643849259117 in words is "six hundred forty-three billion, eight hundred forty-nine million, two hundred fifty-nine thousand, one hundred seventeen".