643036720 has 80 divisors (see below), whose sum is σ = 1596683520. Its totient is φ = 240307200.

The previous prime is 643036717. The next prime is 643036729. The reversal of 643036720 is 27630346.

643036720 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 (80).

It is a Harshad number since it is a multiple of its sum of digits (31).

It is not an unprimeable number, because it can be changed into a prime (643036729) 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, 67450 + ... + 76390.

It is an arithmetic number, because the mean of its divisors is an integer number (19958544).

Almost surely, 2^643036720 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 643036720, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (798341760).

643036720 is an abundant number, since it is smaller than the sum of its proper divisors (953646800).

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

643036720 is a wasteful number, since it uses less digits than its factorization.

643036720 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 9014 (or 9008 counting only the distinct ones).

The product of its (nonzero) digits is 18144, while the sum is 31.

The square root of 643036720 is about 25358.1687035953. The cubic root of 643036720 is about 863.1347290244.

The spelling of 643036720 in words is "six hundred forty-three million, thirty-six thousand, seven hundred twenty".