643322008 has 16 divisors (see below), whose sum is σ = 1378547280. Its totient is φ = 275709408.

The previous prime is 643321949. The next prime is 643322027. The reversal of 643322008 is 800223346.

It is a Harshad number since it is a multiple of its sum of digits (28).

It is a congruent number.

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 5743891 + ... + 5744002.

It is an arithmetic number, because the mean of its divisors is an integer number (86159205).

Almost surely, 2^643322008 is an apocalyptic number.

It is an amenable number.

643322008 is an abundant number, since it is smaller than the sum of its proper divisors (735225272).

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

643322008 is a wasteful number, since it uses less digits than its factorization.

643322008 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 11487906 (or 11487902 counting only the distinct ones).

The product of its (nonzero) digits is 6912, while the sum is 28.

The square root of 643322008 is about 25363.7932494333. The cubic root of 643322008 is about 863.2623555223.

It can be divided in two parts, 6433 and 22008, that added together give a triangular number (28441 = T₂₃₈).

The spelling of 643322008 in words is "six hundred forty-three million, three hundred twenty-two thousand, eight".