643520450 has 24 divisors (see below), whose sum is σ = 1248991488. Its totient is φ = 246216080.

The previous prime is 643520441. The next prime is 643520453. The reversal of 643520450 is 54025346.

643520450 is digitally balanced in base 6, because in such base it contains all the possibile digits an equal number of times.

It is a Curzon number.

It is not an unprimeable number, because it can be changed into a prime (643520453) by changing a digit.

It is a polite number, since it can be written in 11 ways as a sum of consecutive naturals, for example, 278642 + ... + 280941.

It is an arithmetic number, because the mean of its divisors is an integer number (52041312).

Almost surely, 2^643520450 is an apocalyptic number.

643520450 is a deficient number, since it is larger than the sum of its proper divisors (605471038).

643520450 is a wasteful number, since it uses less digits than its factorization.

643520450 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 559618 (or 559613 counting only the distinct ones).

The product of its (nonzero) digits is 14400, while the sum is 29.

The square root of 643520450 is about 25367.7048626792. The cubic root of 643520450 is about 863.3511083268.

Adding to 643520450 its reverse (54025346), we get a palindrome (697545796).

The spelling of 643520450 in words is "six hundred forty-three million, five hundred twenty thousand, four hundred fifty".