643618752 has 224 divisors, whose sum is σ = 2078687232. Its totient is φ = 171764736.

The previous prime is 643618687. The next prime is 643618753. The reversal of 643618752 is 257816346.

643618752 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.

It is a tau number, because it is divible by the number of its divisors (224).

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

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (643618753) by changing a digit.

It is a polite number, since it can be written in 31 ways as a sum of consecutive naturals, for example, 1452643 + ... + 1453085.

Almost surely, 2^643618752 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 643618752, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (1039343616).

643618752 is an abundant number, since it is smaller than the sum of its proper divisors (1435068480).

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

643618752 is a wasteful number, since it uses less digits than its factorization.

643618752 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 535 (or 525 counting only the distinct ones).

The product of its digits is 241920, while the sum is 42.

The square root of 643618752 is about 25369.6423309435. The cubic root of 643618752 is about 863.3950669504.

The spelling of 643618752 in words is "six hundred forty-three million, six hundred eighteen thousand, seven hundred fifty-two".