644172267 has 8 divisors (see below), whose sum is σ = 861695296. Its totient is φ = 428048712.

The previous prime is 644172253. The next prime is 644172289. The reversal of 644172267 is 762271446.

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

It is not a de Polignac number, because 644172267 - 2¹⁰ = 644171243 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (644172967) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 348793 + ... + 350634.

It is an arithmetic number, because the mean of its divisors is an integer number (107711912).

Almost surely, 2^644172267 is an apocalyptic number.

644172267 is a deficient number, since it is larger than the sum of its proper divisors (217523029).

644172267 is a wasteful number, since it uses less digits than its factorization.

644172267 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 699737.

The product of its digits is 112896, while the sum is 39.

The square root of 644172267 is about 25380.5489893343. The cubic root of 644172267 is about 863.6425039023.

The spelling of 644172267 in words is "six hundred forty-four million, one hundred seventy-two thousand, two hundred sixty-seven".