643836284 has 72 divisors (see below), whose sum is σ = 1446148368. Its totient is φ = 248451840.

The previous prime is 643836283. The next prime is 643836287. The reversal of 643836284 is 482638346.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (643836283) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 23 ways as a sum of consecutive naturals, for example, 101387 + ... + 107549.

It is an arithmetic number, because the mean of its divisors is an integer number (20085394).

Almost surely, 2^643836284 is an apocalyptic number.

It is an amenable number.

It is a practical number, because each smaller number is the sum of distinct divisors of 643836284, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (723074184).

643836284 is an abundant number, since it is smaller than the sum of its proper divisors (802312084).

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

643836284 is a wasteful number, since it uses less digits than its factorization.

643836284 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 6235 (or 6226 counting only the distinct ones).

The product of its digits is 663552, while the sum is 44.

The square root of 643836284 is about 25373.9292187868. The cubic root of 643836284 is about 863.4923268575.

The spelling of 643836284 in words is "six hundred forty-three million, eight hundred thirty-six thousand, two hundred eighty-four".