643868346 has 96 divisors (see below), whose sum is σ = 1471486464. Its totient is φ = 187545600.

The previous prime is 643868287. The next prime is 643868363.

643868346 is nontrivially palindromic in base 10.

It is a junction number, because it is equal to n+sod(n) for n = 643868295 and 643868304.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 47 ways as a sum of consecutive naturals, for example, 2887191 + ... + 2887413.

It is an arithmetic number, because the mean of its divisors is an integer number (15327984).

Almost surely, 2^643868346 is an apocalyptic number.

643868346 is a gapful number since it is divisible by the number (66) formed by its first and last digit.

It is a practical number, because each smaller number is the sum of distinct divisors of 643868346, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (735743232).

643868346 is an abundant number, since it is smaller than the sum of its proper divisors (827618118).

It is a pseudoperfect number, because it is the sum of a subset of its proper divisors.

643868346 is a wasteful number, since it uses less digits than its factorization.

643868346 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 388 (or 377 counting only the distinct ones).

The product of its digits is 1990656, while the sum is 48.

The square root of 643868346 is about 25374.5610011287. The cubic root of 643868346 is about 863.5066601242.

The spelling of 643868346 in words is "six hundred forty-three million, eight hundred sixty-eight thousand, three hundred forty-six".