643111423 has 2 divisors, whose sum is σ = 643111424. Its totient is φ = 643111422.

The previous prime is 643111351. The next prime is 643111451. The reversal of 643111423 is 324111346.

It is a strong prime.

It is a cyclic number.

It is not a de Polignac number, because 643111423 - 2²¹ = 641014271 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (643111123) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 321555711 + 321555712.

It is an arithmetic number, because the mean of its divisors is an integer number (321555712).

Almost surely, 2^643111423 is an apocalyptic number.

643111423 is a deficient number, since it is larger than the sum of its proper divisors (1).

643111423 is an equidigital number, since it uses as much as digits as its factorization.

643111423 is an evil number, because the sum of its binary digits is even.

The product of its digits is 1728, while the sum is 25.

The square root of 643111423 is about 25359.6416181302. The cubic root of 643111423 is about 863.1681518212.

Adding to 643111423 its reverse (324111346), we get a palindrome (967222769).

The spelling of 643111423 in words is "six hundred forty-three million, one hundred eleven thousand, four hundred twenty-three".