643500000000 has 1080 divisors, whose sum is σ = 2724667689744. Its totient is φ = 144000000000.

The previous prime is 643499999957. The next prime is 643500000053. The reversal of 643500000000 is 5346.

It is a happy number.

It is a Harshad number since it is a multiple of its sum of digits (18).

It is a Saint-Exupery number, since it is equal to the product of the sides of a Pythagorean triangle: 12500 × 11700 × 4400.

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written in 119 ways as a sum of consecutive naturals, for example, 49499999994 + ... + 49500000006.

Almost surely, 2^643500000000 is an apocalyptic number.

643500000000 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 643500000000, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (1362333844872).

643500000000 is an abundant number, since it is smaller than the sum of its proper divisors (2081167689744).

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

643500000000 is an frugal number, since it uses more digits than its factorization.

643500000000 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 91 (or 34 counting only the distinct ones).

The product of its (nonzero) digits is 360, while the sum is 18.

Adding to 643500000000 its reverse (5346), we get a palindrome (643500005346).

The spelling of 643500000000 in words is "six hundred forty-three billion, five hundred million", and thus it is an aban number.