643287788 has 72 divisors (see below), whose sum is σ = 1402979760. Its totient is φ = 255657600.

The previous prime is 643287781. The next prime is 643287811. The reversal of 643287788 is 887782346.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (643287781) 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 23 ways as a sum of consecutive naturals, for example, 116858 + ... + 122238.

It is an arithmetic number, because the mean of its divisors is an integer number (19485830).

Almost surely, 2^643287788 is an apocalyptic number.

It is an amenable number.

643287788 is an abundant number, since it is smaller than the sum of its proper divisors (759691972).

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

643287788 is a wasteful number, since it uses less digits than its factorization.

643287788 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 5439 (or 5426 counting only the distinct ones).

The product of its digits is 3612672, while the sum is 53.

The square root of 643287788 is about 25363.1186568214. The cubic root of 643287788 is about 863.2470488479.

The spelling of 643287788 in words is "six hundred forty-three million, two hundred eighty-seven thousand, seven hundred eighty-eight".