644319745 has 8 divisors (see below), whose sum is σ = 773616960. Its totient is φ = 515166960.

The previous prime is 644319721. The next prime is 644319749. The reversal of 644319745 is 547913446.

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

It is not a de Polignac number, because 644319745 - 2¹³ = 644311553 is a prime.

It is not an unprimeable number, because it can be changed into a prime (644319749) 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, 26035 + ... + 44344.

It is an arithmetic number, because the mean of its divisors is an integer number (96702120).

Almost surely, 2^644319745 is an apocalyptic number.

It is an amenable number.

644319745 is a deficient number, since it is larger than the sum of its proper divisors (129297215).

644319745 is a wasteful number, since it uses less digits than its factorization.

644319745 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 72215.

The product of its digits is 362880, while the sum is 43.

The square root of 644319745 is about 25383.4541581716. The cubic root of 644319745 is about 863.7084068483.

The spelling of 644319745 in words is "six hundred forty-four million, three hundred nineteen thousand, seven hundred forty-five".