646205041 has 2 divisors, whose sum is σ = 646205042. Its totient is φ = 646205040.

The previous prime is 646205039. The next prime is 646205051. The reversal of 646205041 is 140502646.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 402845041 + 243360000 = 20071^2 + 15600^2 .

It is a cyclic number.

It is not a de Polignac number, because 646205041 - 2¹ = 646205039 is a prime.

Together with 646205039, it forms a pair of twin primes.

It is not a weakly prime, because it can be changed into another prime (646205051) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 323102520 + 323102521.

It is an arithmetic number, because the mean of its divisors is an integer number (323102521).

Almost surely, 2^646205041 is an apocalyptic number.

It is an amenable number.

646205041 is a deficient number, since it is larger than the sum of its proper divisors (1).

646205041 is an equidigital number, since it uses as much as digits as its factorization.

646205041 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 5760, while the sum is 28.

The square root of 646205041 is about 25420.5633493831. The cubic root of 646205041 is about 864.5499974819.

Adding to 646205041 its reverse (140502646), we get a palindrome (786707687).

The spelling of 646205041 in words is "six hundred forty-six million, two hundred five thousand, forty-one".