643504423 has 2 divisors, whose sum is σ = 643504424. Its totient is φ = 643504422.

The previous prime is 643504409. The next prime is 643504447. The reversal of 643504423 is 324405346.

643504423 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.

It is a weak prime.

It is a cyclic number.

It is not a de Polignac number, because 643504423 - 2²¹ = 641407271 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (643504123) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 321752211 + 321752212.

It is an arithmetic number, because the mean of its divisors is an integer number (321752212).

Almost surely, 2^643504423 is an apocalyptic number.

643504423 is a deficient number, since it is larger than the sum of its proper divisors (1).

643504423 is an equidigital number, since it uses as much as digits as its factorization.

643504423 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 34560, while the sum is 31.

The square root of 643504423 is about 25367.3889669394. The cubic root of 643504423 is about 863.3439409591.

Adding to 643504423 its reverse (324405346), we get a palindrome (967909769).

The spelling of 643504423 in words is "six hundred forty-three million, five hundred four thousand, four hundred twenty-three".