644747347 has 8 divisors (see below), whose sum is σ = 649560752. Its totient is φ = 639943200.

The previous prime is 644747333. The next prime is 644747351. The reversal of 644747347 is 743747446.

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

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-644747347 is a prime.

It is a Duffinian number.

It is a junction number, because it is equal to n+sod(n) for n = 644747297 and 644747306.

It is not an unprimeable number, because it can be changed into a prime (644747647) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 201097 + ... + 204277.

It is an arithmetic number, because the mean of its divisors is an integer number (81195094).

Almost surely, 2^644747347 is an apocalyptic number.

644747347 is a deficient number, since it is larger than the sum of its proper divisors (4813405).

644747347 is a wasteful number, since it uses less digits than its factorization.

644747347 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 4629.

The product of its digits is 1580544, while the sum is 46.

The square root of 644747347 is about 25391.8756101238. The cubic root of 644747347 is about 863.8994309347.

Subtracting 644747347 from its reverse (743747446), we obtain a palindrome (99000099).

The spelling of 644747347 in words is "six hundred forty-four million, seven hundred forty-seven thousand, three hundred forty-seven".