644461743 has 4 divisors (see below), whose sum is σ = 859282328. Its totient is φ = 429641160.

The previous prime is 644461723. The next prime is 644461747. The reversal of 644461743 is 347164446.

It is a semiprime because it is the product of two primes.

It is a de Polignac number, because none of the positive numbers 2^k-644461743 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 (644461747) 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 3 ways as a sum of consecutive naturals, for example, 107410288 + ... + 107410293.

It is an arithmetic number, because the mean of its divisors is an integer number (214820582).

Almost surely, 2^644461743 is an apocalyptic number.

644461743 is a deficient number, since it is larger than the sum of its proper divisors (214820585).

644461743 is a wasteful number, since it uses less digits than its factorization.

644461743 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 214820584.

The product of its digits is 193536, while the sum is 39.

The square root of 644461743 is about 25386.2510623369. The cubic root of 644461743 is about 863.7718514650.

The spelling of 644461743 in words is "six hundred forty-four million, four hundred sixty-one thousand, seven hundred forty-three".