643888346 has 16 divisors (see below), whose sum is σ = 970449768. Its totient is φ = 320409600.

The previous prime is 643888339. The next prime is 643888369.

643888346 is nontrivially palindromic in base 10.

643888346 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.

It can be written as a sum of positive squares in 4 ways, for example, as 490401025 + 153487321 = 22145^2 + 12389^2 .

It is a super-2 number, since 2×643888346² = 829184404229231432, which contains 22 as substring.

It is a junction number, because it is equal to n+sod(n) for n = 643888294 and 643888303.

It is an unprimeable number.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 539126 + ... + 540318.

Almost surely, 2^643888346 is an apocalyptic number.

643888346 is a deficient number, since it is larger than the sum of its proper divisors (326561422).

643888346 is a wasteful number, since it uses less digits than its factorization.

643888346 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 2257.

The product of its digits is 2654208, while the sum is 50.

The square root of 643888346 is about 25374.9550935563. The cubic root of 643888346 is about 863.5156008517.

The spelling of 643888346 in words is "six hundred forty-three million, eight hundred eighty-eight thousand, three hundred forty-six".