643441536 has 256 divisors, whose sum is σ = 2056320000. Its totient is φ = 197406720.

The previous prime is 643441523. The next prime is 643441541. The reversal of 643441536 is 635144346.

643441536 is a `hidden beast` number, since 643 + 4 + 4 + 1 + 5 + 3 + 6 = 666.

It is a Harshad number since it is a multiple of its sum of digits (36).

It is a self number, because there is not a number n which added to its sum of digits gives 643441536.

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 31 ways as a sum of consecutive naturals, for example, 2692105 + ... + 2692343.

It is an arithmetic number, because the mean of its divisors is an integer number (8032500).

Almost surely, 2^643441536 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 643441536, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (1028160000).

643441536 is an abundant number, since it is smaller than the sum of its proper divisors (1412878464).

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

643441536 is a wasteful number, since it uses less digits than its factorization.

643441536 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 322 (or 304 counting only the distinct ones).

The product of its digits is 103680, while the sum is 36.

The square root of 643441536 is about 25366.1494121595. The cubic root of 643441536 is about 863.3158163769.

The spelling of 643441536 in words is "six hundred forty-three million, four hundred forty-one thousand, five hundred thirty-six".