643222840 has 64 divisors (see below), whose sum is σ = 1588053600. Its totient is φ = 233006592.

The previous prime is 643222831. The next prime is 643222841. The reversal of 643222840 is 48222346.

643222840 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (643222841) by changing a digit.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 15891 + ... + 39229.

Almost surely, 2^643222840 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 643222840, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (794026800).

643222840 is an abundant number, since it is smaller than the sum of its proper divisors (944830760).

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

643222840 is a wasteful number, since it uses less digits than its factorization.

643222840 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 23416 (or 23412 counting only the distinct ones).

The product of its (nonzero) digits is 18432, while the sum is 31.

The square root of 643222840 is about 25361.8382614510. The cubic root of 643222840 is about 863.2179959847.

The spelling of 643222840 in words is "six hundred forty-three million, two hundred twenty-two thousand, eight hundred forty".