640268543 has 2 divisors, whose sum is σ = 640268544. Its totient is φ = 640268542.

The previous prime is 640268537. The next prime is 640268647. The reversal of 640268543 is 345862046.

It is a weak prime.

It is a cyclic number.

It is not a de Polignac number, because 640268543 - 2⁸ = 640268287 is a prime.

It is a junction number, because it is equal to n+sod(n) for n = 640268497 and 640268506.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (640268743) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 320134271 + 320134272.

It is an arithmetic number, because the mean of its divisors is an integer number (320134272).

Almost surely, 2^640268543 is an apocalyptic number.

640268543 is a deficient number, since it is larger than the sum of its proper divisors (1).

640268543 is an equidigital number, since it uses as much as digits as its factorization.

640268543 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 138240, while the sum is 38.

The square root of 640268543 is about 25303.5282717648. The cubic root of 640268543 is about 861.8943921488.

The spelling of 640268543 in words is "six hundred forty million, two hundred sixty-eight thousand, five hundred forty-three".