643784356 has 12 divisors (see below), whose sum is σ = 1192894668. Its totient is φ = 302957312.

The previous prime is 643784327. The next prime is 643784357. The reversal of 643784356 is 653487346.

It can be written as a sum of positive squares in 2 ways, for example, as 509224356 + 134560000 = 22566^2 + 11600^2 .

It is not an unprimeable number, because it can be changed into a prime (643784357) 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, 4733641 + ... + 4733776.

It is an arithmetic number, because the mean of its divisors is an integer number (99407889).

Almost surely, 2^643784356 is an apocalyptic number.

It is an amenable number.

643784356 is a deficient number, since it is larger than the sum of its proper divisors (549110312).

643784356 is a wasteful number, since it uses less digits than its factorization.

643784356 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 9467438 (or 9467436 counting only the distinct ones).

The product of its digits is 1451520, while the sum is 46.

The square root of 643784356 is about 25372.9059431512. The cubic root of 643784356 is about 863.4691115173.

The spelling of 643784356 in words is "six hundred forty-three million, seven hundred eighty-four thousand, three hundred fifty-six".