643129968 has 80 divisors (see below), whose sum is σ = 1846992896. Its totient is φ = 191496960.

The previous prime is 643129961. The next prime is 643129969. The reversal of 643129968 is 869921346.

It is a Harshad number since it is a multiple of its sum of digits (48).

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (643129961) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 2721 + ... + 35967.

Almost surely, 2^643129968 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 643129968, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (923496448).

643129968 is an abundant number, since it is smaller than the sum of its proper divisors (1203862928).

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

643129968 is a wasteful number, since it uses less digits than its factorization.

643129968 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 33302 (or 33296 counting only the distinct ones).

The product of its digits is 559872, while the sum is 48.

The square root of 643129968 is about 25360.0072555195. The cubic root of 643129968 is about 863.1764486207.

The spelling of 643129968 in words is "six hundred forty-three million, one hundred twenty-nine thousand, nine hundred sixty-eight".