643566336 has 144 divisors (see below), whose sum is σ = 1991673600. Its totient is φ = 180670464.

The previous prime is 643566283. The next prime is 643566349. The reversal of 643566336 is 633665346.

It is a Harshad number since it is a multiple of its sum of digits (42).

It is an unprimeable number.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 316170 + ... + 318198.

Almost surely, 2^643566336 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 643566336, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (995836800).

643566336 is an abundant number, since it is smaller than the sum of its proper divisors (1348107264).

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

643566336 is a wasteful number, since it uses less digits than its factorization.

643566336 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 2114 (or 2100 counting only the distinct ones).

The product of its digits is 699840, while the sum is 42.

The square root of 643566336 is about 25368.6092642068. The cubic root of 643566336 is about 863.3716281551.

It can be divided in two parts, 6435 and 66336, that added together give a triangular number (72771 = T₃₈₁).

The spelling of 643566336 in words is "six hundred forty-three million, five hundred sixty-six thousand, three hundred thirty-six".