640444244063 has 4 divisors (see below), whose sum is σ = 689709185928. Its totient is φ = 591179302200.

The previous prime is 640444244021. The next prime is 640444244107. The reversal of 640444244063 is 360442444046.

It is a semiprime because it is the product of two primes.

It is a cyclic number.

It is not a de Polignac number, because 640444244063 - 2³⁸ = 365566337119 is a prime.

It is a Duffinian number.

It is a self number, because there is not a number n which added to its sum of digits gives 640444244063.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (640444244863) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 24632470913 + ... + 24632470938.

It is an arithmetic number, because the mean of its divisors is an integer number (172427296482).

Almost surely, 2^640444244063 is an apocalyptic number.

640444244063 is a deficient number, since it is larger than the sum of its proper divisors (49264941865).

640444244063 is a wasteful number, since it uses less digits than its factorization.

640444244063 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 49264941864.

The product of its (nonzero) digits is 884736, while the sum is 41.

The spelling of 640444244063 in words is "six hundred forty billion, four hundred forty-four million, two hundred forty-four thousand, sixty-three".