643878047 has 2 divisors, whose sum is σ = 643878048. Its totient is φ = 643878046.

The previous prime is 643877989. The next prime is 643878071. The reversal of 643878047 is 740878346.

643878047 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 643878047 - 2²⁸ = 375442591 is a prime.

It is a Chen prime.

It is a junction number, because it is equal to n+sod(n) for n = 643877992 and 643878010.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (643848047) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 321939023 + 321939024.

It is an arithmetic number, because the mean of its divisors is an integer number (321939024).

Almost surely, 2^643878047 is an apocalyptic number.

643878047 is a deficient number, since it is larger than the sum of its proper divisors (1).

643878047 is an equidigital number, since it uses as much as digits as its factorization.

643878047 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 903168, while the sum is 47.

The square root of 643878047 is about 25374.7521564251. The cubic root of 643878047 is about 863.5109968472.

The spelling of 643878047 in words is "six hundred forty-three million, eight hundred seventy-eight thousand, forty-seven".