644171371 has 4 divisors (see below), whose sum is σ = 644225200. Its totient is φ = 644117544.

The previous prime is 644171329. The next prime is 644171389. The reversal of 644171371 is 173171446.

644171371 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 a brilliant number, because the two primes have the same length.

It is a cyclic number.

It is not a de Polignac number, because 644171371 - 2⁷ = 644171243 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (644171071) 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, 25 + ... + 35893.

It is an arithmetic number, because the mean of its divisors is an integer number (161056300).

Almost surely, 2^644171371 is an apocalyptic number.

644171371 is a deficient number, since it is larger than the sum of its proper divisors (53829).

644171371 is a wasteful number, since it uses less digits than its factorization.

644171371 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 53828.

The product of its digits is 14112, while the sum is 34.

The square root of 644171371 is about 25380.5313380158. The cubic root of 644171371 is about 863.6421034794.

The spelling of 644171371 in words is "six hundred forty-four million, one hundred seventy-one thousand, three hundred seventy-one".