643287789 has 12 divisors (see below), whose sum is σ = 959167872. Its totient is φ = 415024200.

The previous prime is 643287781. The next prime is 643287811. The reversal of 643287789 is 987782346.

It is not a de Polignac number, because 643287789 - 2³ = 643287781 is a prime.

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 polite number, since it can be written in 11 ways as a sum of consecutive naturals, for example, 1152567 + ... + 1153124.

It is an arithmetic number, because the mean of its divisors is an integer number (79930656).

Almost surely, 2^643287789 is an apocalyptic number.

It is an amenable number.

643287789 is a deficient number, since it is larger than the sum of its proper divisors (315880083).

643287789 is a wasteful number, since it uses less digits than its factorization.

643287789 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 2305728 (or 2305725 counting only the distinct ones).

The product of its digits is 4064256, while the sum is 54.

The square root of 643287789 is about 25363.1186765350. The cubic root of 643287789 is about 863.2470492952.

The spelling of 643287789 in words is "six hundred forty-three million, two hundred eighty-seven thousand, seven hundred eighty-nine".