643853723 has 2 divisors, whose sum is σ = 643853724. Its totient is φ = 643853722.

The previous prime is 643853677. The next prime is 643853753. The reversal of 643853723 is 327358346.

643853723 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.

It is a strong prime.

It is a cyclic number.

It is not a de Polignac number, because 643853723 - 2²⁴ = 627076507 is a prime.

It is not a weakly prime, because it can be changed into another prime (643853753) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 321926861 + 321926862.

It is an arithmetic number, because the mean of its divisors is an integer number (321926862).

Almost surely, 2^643853723 is an apocalyptic number.

643853723 is a deficient number, since it is larger than the sum of its proper divisors (1).

643853723 is an equidigital number, since it uses as much as digits as its factorization.

643853723 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 362880, while the sum is 41.

The square root of 643853723 is about 25374.2728565766. The cubic root of 643853723 is about 863.5001229940.

The spelling of 643853723 in words is "six hundred forty-three million, eight hundred fifty-three thousand, seven hundred twenty-three".