640513543 has 2 divisors, whose sum is σ = 640513544. Its totient is φ = 640513542.

The previous prime is 640513487. The next prime is 640513567. The reversal of 640513543 is 345315046.

640513543 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.

It is a strong prime.

It is a cyclic number.

It is not a de Polignac number, because 640513543 - 2¹³ = 640505351 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (640513243) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 320256771 + 320256772.

It is an arithmetic number, because the mean of its divisors is an integer number (320256772).

Almost surely, 2^640513543 is an apocalyptic number.

640513543 is a deficient number, since it is larger than the sum of its proper divisors (1).

640513543 is an equidigital number, since it uses as much as digits as its factorization.

640513543 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 21600, while the sum is 31.

The square root of 640513543 is about 25308.3690308167. The cubic root of 640513543 is about 862.0043133165.

Adding to 640513543 its reverse (345315046), we get a palindrome (985828589).

The spelling of 640513543 in words is "six hundred forty million, five hundred thirteen thousand, five hundred forty-three".