643181047 has 2 divisors, whose sum is σ = 643181048. Its totient is φ = 643181046.

The previous prime is 643180991. The next prime is 643181059. The reversal of 643181047 is 740181346.

It is a happy number.

It is a strong prime.

It is a cyclic number.

It is not a de Polignac number, because 643181047 - 2⁷ = 643180919 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (643181647) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 321590523 + 321590524.

It is an arithmetic number, because the mean of its divisors is an integer number (321590524).

Almost surely, 2^643181047 is an apocalyptic number.

643181047 is a deficient number, since it is larger than the sum of its proper divisors (1).

643181047 is an equidigital number, since it uses as much as digits as its factorization.

643181047 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 16128, while the sum is 34.

The square root of 643181047 is about 25361.0143133117. The cubic root of 643181047 is about 863.1992998974.

It can be divided in two parts, 6431 and 81047, that added together give a palindrome (87478).

The spelling of 643181047 in words is "six hundred forty-three million, one hundred eighty-one thousand, forty-seven".