643042423 has 2 divisors, whose sum is σ = 643042424. Its totient is φ = 643042422.

The previous prime is 643042381. The next prime is 643042447. The reversal of 643042423 is 324240346.

It is a strong prime.

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-643042423 is a prime.

It is a junction number, because it is equal to n+sod(n) for n = 643042391 and 643042400.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (643042523) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 321521211 + 321521212.

It is an arithmetic number, because the mean of its divisors is an integer number (321521212).

Almost surely, 2^643042423 is an apocalyptic number.

643042423 is a deficient number, since it is larger than the sum of its proper divisors (1).

643042423 is an equidigital number, since it uses as much as digits as its factorization.

643042423 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 13824, while the sum is 28.

The square root of 643042423 is about 25358.2811523179. The cubic root of 643042423 is about 863.1372806893.

Adding to 643042423 its reverse (324240346), we get a palindrome (967282769).

The spelling of 643042423 in words is "six hundred forty-three million, forty-two thousand, four hundred twenty-three".