644326463 has 8 divisors (see below), whose sum is σ = 705151056. Its totient is φ = 583876800.

The previous prime is 644326457. The next prime is 644326483. The reversal of 644326463 is 364623446.

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 644326463 - 2¹⁰ = 644325439 is a prime.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (644326453) 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, 90128 + ... + 97013.

It is an arithmetic number, because the mean of its divisors is an integer number (88143882).

Almost surely, 2^644326463 is an apocalyptic number.

644326463 is a deficient number, since it is larger than the sum of its proper divisors (60824593).

644326463 is a wasteful number, since it uses less digits than its factorization.

644326463 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 187465.

The product of its digits is 248832, while the sum is 38.

The square root of 644326463 is about 25383.5864881226. The cubic root of 644326463 is about 863.7114086565.

The spelling of 644326463 in words is "six hundred forty-four million, three hundred twenty-six thousand, four hundred sixty-three".