640493045471 has 2 divisors, whose sum is σ = 640493045472. Its totient is φ = 640493045470.

The previous prime is 640493045417. The next prime is 640493045519. The reversal of 640493045471 is 174540394046.

Together with previous prime (640493045417) it forms an Ormiston pair, because they use the same digits, order apart.

It is a strong prime.

It is a cyclic number.

It is not a de Polignac number, because 640493045471 - 2¹⁰ = 640493044447 is a prime.

It is a super-3 number, since 3×640493045471³ (a number of 36 digits) contains 333 as substring. Note that it is a super-d number also for d = 2.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (640493047471) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (19) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 320246522735 + 320246522736.

It is an arithmetic number, because the mean of its divisors is an integer number (320246522736).

Almost surely, 2^640493045471 is an apocalyptic number.

640493045471 is a deficient number, since it is larger than the sum of its proper divisors (1).

640493045471 is an equidigital number, since it uses as much as digits as its factorization.

640493045471 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 1451520, while the sum is 47.

The spelling of 640493045471 in words is "six hundred forty billion, four hundred ninety-three million, forty-five thousand, four hundred seventy-one".