640844404248 has 32 divisors (see below), whose sum is σ = 1602131517360. Its totient is φ = 213612067200.

The previous prime is 640844404199. The next prime is 640844404289. The reversal of 640844404248 is 842404448046.

It is a Smith number, since the sum of its digits (48) coincides with the sum of the digits of its prime factors.

It is a junction number, because it is equal to n+sod(n) for n = 640844404197 and 640844404206.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 2790598 + ... + 3011498.

Almost surely, 2^640844404248 is an apocalyptic number.

It is an amenable number.

640844404248 is an abundant number, since it is smaller than the sum of its proper divisors (961287113112).

It is a pseudoperfect number, because it is the sum of a subset of its proper divisors.

640844404248 is a wasteful number, since it uses less digits than its factorization.

640844404248 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 341787 (or 341783 counting only the distinct ones).

The product of its (nonzero) digits is 3145728, while the sum is 48.

The spelling of 640844404248 in words is "six hundred forty billion, eight hundred forty-four million, four hundred four thousand, two hundred forty-eight".