640384841 has 2 divisors, whose sum is σ = 640384842. Its totient is φ = 640384840.

The previous prime is 640384819. The next prime is 640384847. The reversal of 640384841 is 148483046.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 630010000 + 10374841 = 25100^2 + 3221^2 .

It is a cyclic number.

It is not a de Polignac number, because 640384841 - 2¹⁸ = 640122697 is a prime.

It is a junction number, because it is equal to n+sod(n) for n = 640384795 and 640384804.

It is not a weakly prime, because it can be changed into another prime (640384847) 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, 320192420 + 320192421.

It is an arithmetic number, because the mean of its divisors is an integer number (320192421).

Almost surely, 2^640384841 is an apocalyptic number.

It is an amenable number.

640384841 is a deficient number, since it is larger than the sum of its proper divisors (1).

640384841 is an equidigital number, since it uses as much as digits as its factorization.

640384841 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 73728, while the sum is 38.

The square root of 640384841 is about 25305.8262263851. The cubic root of 640384841 is about 861.9465736523.

The spelling of 640384841 in words is "six hundred forty million, three hundred eighty-four thousand, eight hundred forty-one".