643404250 has 16 divisors (see below), whose sum is σ = 1204453224. Its totient is φ = 257361600.

The previous prime is 643404221. The next prime is 643404257. The reversal of 643404250 is 52404346.

643404250 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.

It can be written as a sum of positive squares in 4 ways, for example, as 228100609 + 415303641 = 15103^2 + 20379^2 .

It is not an unprimeable number, because it can be changed into a prime (643404257) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 1286559 + ... + 1287058.

Almost surely, 2^643404250 is an apocalyptic number.

643404250 is a deficient number, since it is larger than the sum of its proper divisors (561048974).

643404250 is a wasteful number, since it uses less digits than its factorization.

643404250 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 2573634 (or 2573624 counting only the distinct ones).

The product of its (nonzero) digits is 11520, while the sum is 28.

The square root of 643404250 is about 25365.4144456581. The cubic root of 643404250 is about 863.2991403136.

Adding to 643404250 its reverse (52404346), we get a palindrome (695808596).

The spelling of 643404250 in words is "six hundred forty-three million, four hundred four thousand, two hundred fifty".