640543895290 has 32 divisors (see below), whose sum is σ = 1275228354960. Its totient is φ = 230116391424.

The previous prime is 640543895281. The next prime is 640543895323. The reversal of 640543895290 is 92598345046.

640543895290 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.

It can be written as a sum of positive squares in 8 ways, for example, as 186134433489 + 454409461801 = 431433^2 + 674099^2 .

It is a Smith number, since the sum of its digits (55) coincides with the sum of the digits of its prime factors. Since it is squarefree, it is also a hoax number.

It is an unprimeable number.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 66579795 + ... + 66589414.

Almost surely, 2^640543895290 is an apocalyptic number.

640543895290 is a deficient number, since it is larger than the sum of its proper divisors (634684459670).

640543895290 is a wasteful number, since it uses less digits than its factorization.

640543895290 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 133169266.

The product of its (nonzero) digits is 9331200, while the sum is 55.

The spelling of 640543895290 in words is "six hundred forty billion, five hundred forty-three million, eight hundred ninety-five thousand, two hundred ninety".