640681340425 has 12 divisors (see below), whose sum is σ = 907936985536. Its totient is φ = 439324347600.

The previous prime is 640681340423. The next prime is 640681340471. The reversal of 640681340425 is 524043186046.

It is not a de Polignac number, because 640681340425 - 2¹ = 640681340423 is a prime.

It is a hoax number, since the sum of its digits (43) coincides with the sum of the digits of its distinct prime factors.

It is not an unprimeable number, because it can be changed into a prime (640681340423) 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 in 11 ways as a sum of consecutive naturals, for example, 1830517941 + ... + 1830518290.

Almost surely, 2^640681340425 is an apocalyptic number.

It is an amenable number.

640681340425 is a deficient number, since it is larger than the sum of its proper divisors (267255645111).

640681340425 is a wasteful number, since it uses less digits than its factorization.

640681340425 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 3661036248 (or 3661036243 counting only the distinct ones).

The product of its (nonzero) digits is 552960, while the sum is 43.

The spelling of 640681340425 in words is "six hundred forty billion, six hundred eighty-one million, three hundred forty thousand, four hundred twenty-five".