643422528 has 420 divisors, whose sum is σ = 2364981300. Its totient is φ = 171859968.

The previous prime is 643422499. The next prime is 643422529. The reversal of 643422528 is 825224346.

643422528 is a `hidden beast` number, since 64 + 342 + 252 + 8 = 666.

It can be written as a sum of positive squares in 2 ways, for example, as 276623424 + 366799104 = 16632^2 + 19152^2 .

It is a Harshad number since it is a multiple of its sum of digits (36).

It is a junction number, because it is equal to n+sod(n) for n = 643422492 and 643422501.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (643422529) 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 59 ways as a sum of consecutive naturals, for example, 4318198 + ... + 4318346.

Almost surely, 2^643422528 is an apocalyptic number.

643422528 is a gapful number since it is divisible by the number (68) 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 643422528, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (1182490650).

643422528 is an abundant number, since it is smaller than the sum of its proper divisors (1721558772).

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

643422528 is a wasteful number, since it uses less digits than its factorization.

643422528 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 204 (or 178 counting only the distinct ones).

The product of its digits is 92160, while the sum is 36.

The square root of 643422528 is about 25365.7747368378. The cubic root of 643422528 is about 863.3073151805.

The spelling of 643422528 in words is "six hundred forty-three million, four hundred twenty-two thousand, five hundred twenty-eight".