643851334247 has 16 divisors (see below), whose sum is σ = 710708749344. Its totient is φ = 583236068800.

The previous prime is 643851334241. The next prime is 643851334267. The reversal of 643851334247 is 742433158346.

It is a de Polignac number, because none of the positive numbers 2^k-643851334247 is a prime.

It is a super-3 number, since 3×643851334247³ (a number of 36 digits) contains 333 as substring. Note that it is a super-d number also for d = 2.

It is a junction number, because it is equal to n+sod(n) for n = 643851334195 and 643851334204.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (643851334241) by changing a digit.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 486728 + ... + 1234749.

It is an arithmetic number, because the mean of its divisors is an integer number (44419296834).

Almost surely, 2^643851334247 is an apocalyptic number.

643851334247 is a deficient number, since it is larger than the sum of its proper divisors (66857415097).

643851334247 is a wasteful number, since it uses less digits than its factorization.

643851334247 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1721791 (or 1721769 counting only the distinct ones).

The product of its digits is 5806080, while the sum is 50.

The spelling of 643851334247 in words is "six hundred forty-three billion, eight hundred fifty-one million, three hundred thirty-four thousand, two hundred forty-seven".