644355212263 has 8 divisors (see below), whose sum is σ = 736476651680. Its totient is φ = 552251446560.

The previous prime is 644355212233. The next prime is 644355212297. The reversal of 644355212263 is 362212553446.

It is a sphenic number, since it is the product of 3 distinct primes.

It is a cyclic number.

It is not a de Polignac number, because 644355212263 - 2¹⁷ = 644355081191 is a prime.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (644355212233) 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, 4340208 + ... + 4486213.

It is an arithmetic number, because the mean of its divisors is an integer number (92059581460).

Almost surely, 2^644355212263 is an apocalyptic number.

644355212263 is a deficient number, since it is larger than the sum of its proper divisors (92121439417).

644355212263 is a wasteful number, since it uses less digits than its factorization.

644355212263 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 8836857.

The product of its digits is 1036800, while the sum is 43.

The spelling of 644355212263 in words is "six hundred forty-four billion, three hundred fifty-five million, two hundred twelve thousand, two hundred sixty-three".