644046271 has 4 divisors (see below), whose sum is σ = 702595944. Its totient is φ = 585496600.

The previous prime is 644046269. The next prime is 644046307. The reversal of 644046271 is 172640446.

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

It is a cyclic number.

It is not a de Polignac number, because 644046271 - 2¹ = 644046269 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 (644046371) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (19) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 29274820 + ... + 29274841.

It is an arithmetic number, because the mean of its divisors is an integer number (175648986).

Almost surely, 2^644046271 is an apocalyptic number.

644046271 is a deficient number, since it is larger than the sum of its proper divisors (58549673).

644046271 is a wasteful number, since it uses less digits than its factorization.

644046271 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 58549672.

The product of its (nonzero) digits is 32256, while the sum is 34.

The square root of 644046271 is about 25378.0667309391. The cubic root of 644046271 is about 863.5861925697.

The spelling of 644046271 in words is "six hundred forty-four million, forty-six thousand, two hundred seventy-one".