640003943 has 2 divisors, whose sum is σ = 640003944. Its totient is φ = 640003942.

The previous prime is 640003909. The next prime is 640004017. The reversal of 640003943 is 349300046.

It is a happy number.

It is a weak prime.

It is a cyclic number.

It is not a de Polignac number, because 640003943 - 2⁸ = 640003687 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (640003843) 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, 320001971 + 320001972.

It is an arithmetic number, because the mean of its divisors is an integer number (320001972).

Almost surely, 2^640003943 is an apocalyptic number.

640003943 is a deficient number, since it is larger than the sum of its proper divisors (1).

640003943 is an equidigital number, since it uses as much as digits as its factorization.

640003943 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 7776, while the sum is 29.

The square root of 640003943 is about 25298.2992116071. The cubic root of 640003943 is about 861.7756457874.

Adding to 640003943 its reverse (349300046), we get a palindrome (989303989).

The spelling of 640003943 in words is "six hundred forty million, three thousand, nine hundred forty-three".