644224823 has 8 divisors (see below), whose sum is σ = 704263680. Its totient is φ = 584431480.

The previous prime is 644224813. The next prime is 644224853. The reversal of 644224823 is 328422446.

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 644224823 - 2¹⁸ = 643962679 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 (644224813) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 55865 + ... + 66402.

It is an arithmetic number, because the mean of its divisors is an integer number (88032960).

Almost surely, 2^644224823 is an apocalyptic number.

644224823 is a deficient number, since it is larger than the sum of its proper divisors (60038857).

644224823 is a wasteful number, since it uses less digits than its factorization.

644224823 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 122757.

The product of its digits is 73728, while the sum is 35.

The square root of 644224823 is about 25381.5843280123. The cubic root of 644224823 is about 863.6659905602.

The spelling of 644224823 in words is "six hundred forty-four million, two hundred twenty-four thousand, eight hundred twenty-three".