643257847 has 2 divisors, whose sum is σ = 643257848. Its totient is φ = 643257846.

The previous prime is 643257833. The next prime is 643257851. The reversal of 643257847 is 748752346.

It is a strong prime.

It is a cyclic number.

It is not a de Polignac number, because 643257847 - 2¹¹ = 643255799 is a prime.

It is a junction number, because it is equal to n+sod(n) for n = 643257797 and 643257806.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (643257827) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (19) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 321628923 + 321628924.

It is an arithmetic number, because the mean of its divisors is an integer number (321628924).

Almost surely, 2^643257847 is an apocalyptic number.

643257847 is a deficient number, since it is larger than the sum of its proper divisors (1).

643257847 is an equidigital number, since it uses as much as digits as its factorization.

643257847 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 1128960, while the sum is 46.

The square root of 643257847 is about 25362.5284031384. The cubic root of 643257847 is about 863.2336557334.

The spelling of 643257847 in words is "six hundred forty-three million, two hundred fifty-seven thousand, eight hundred forty-seven".