644912347 has 4 divisors (see below), whose sum is σ = 645232536. Its totient is φ = 644592160.

The previous prime is 644912327. The next prime is 644912351. The reversal of 644912347 is 743219446.

644912347 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.

It is a semiprime because it is the product of two primes, and also an emirpimes, since its reverse is a distinct semiprime: 743219446 = 2 ⋅371609723.

It is a cyclic number.

It is not a de Polignac number, because 644912347 - 2¹⁵ = 644879579 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (644912327) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 157054 + ... + 161107.

It is an arithmetic number, because the mean of its divisors is an integer number (161308134).

Almost surely, 2^644912347 is an apocalyptic number.

644912347 is a deficient number, since it is larger than the sum of its proper divisors (320189).

644912347 is a wasteful number, since it uses less digits than its factorization.

644912347 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 320188.

The product of its digits is 145152, while the sum is 40.

The square root of 644912347 is about 25395.1244730165. The cubic root of 644912347 is about 863.9731193590.

The spelling of 644912347 in words is "six hundred forty-four million, nine hundred twelve thousand, three hundred forty-seven".