643159972 has 48 divisors (see below), whose sum is σ = 1388903040. Its totient is φ = 253769472.

The previous prime is 643159967. The next prime is 643159973. The reversal of 643159972 is 279951346.

It is a happy number.

It is not an unprimeable number, because it can be changed into a prime (643159973) 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, 150408 + ... + 154624.

It is an arithmetic number, because the mean of its divisors is an integer number (28935480).

Almost surely, 2^643159972 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 643159972, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (694451520).

643159972 is an abundant number, since it is smaller than the sum of its proper divisors (745743068).

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

643159972 is a wasteful number, since it uses less digits than its factorization.

643159972 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 4660 (or 4658 counting only the distinct ones).

The product of its digits is 408240, while the sum is 46.

The square root of 643159972 is about 25360.5988099650. The cubic root of 643159972 is about 863.1898716946.

The spelling of 643159972 in words is "six hundred forty-three million, one hundred fifty-nine thousand, nine hundred seventy-two".