643493760 has 512 divisors, whose sum is σ = 2632089600. Its totient is φ = 130056192.

The previous prime is 643493743. The next prime is 643493761. The reversal of 643493760 is 67394346.

643493760 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.

It is a hoax number, since the sum of its digits (42) coincides with the sum of the digits of its distinct prime factors.

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 (643493761) by changing a digit.

It is a polite number, since it can be written in 63 ways as a sum of consecutive naturals, for example, 5066817 + ... + 5066943.

It is an arithmetic number, because the mean of its divisors is an integer number (5140800).

Almost surely, 2^643493760 is an apocalyptic number.

643493760 is a gapful number since it is divisible by the number (60) formed by its first and last digit.

It is an amenable number.

It is a practical number, because each smaller number is the sum of distinct divisors of 643493760, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (1316044800).

643493760 is an abundant number, since it is smaller than the sum of its proper divisors (1988595840).

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

643493760 is a wasteful number, since it uses less digits than its factorization.

643493760 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 198 (or 186 counting only the distinct ones).

The product of its (nonzero) digits is 326592, while the sum is 42.

The square root of 643493760 is about 25367.1787946551. The cubic root of 643493760 is about 863.3391723375.

The spelling of 643493760 in words is "six hundred forty-three million, four hundred ninety-three thousand, seven hundred sixty".