640445745490 has 16 divisors (see below), whose sum is σ = 1152811453248. Its totient is φ = 256176273456.

The previous prime is 640445745389. The next prime is 640445745491. The reversal of 640445745490 is 94547544046.

It is not an unprimeable number, because it can be changed into a prime (640445745491) 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 in 7 ways as a sum of consecutive naturals, for example, 2368789 + ... + 2625271.

It is an arithmetic number, because the mean of its divisors is an integer number (72050715828).

Almost surely, 2^640445745490 is an apocalyptic number.

640445745490 is a deficient number, since it is larger than the sum of its proper divisors (512365707758).

640445745490 is a wasteful number, since it uses less digits than its factorization.

640445745490 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 506193.

The product of its (nonzero) digits is 9676800, while the sum is 52.

The spelling of 640445745490 in words is "six hundred forty billion, four hundred forty-five million, seven hundred forty-five thousand, four hundred ninety".