644371 has 16 divisors (see below), whose sum is σ = 812224. Its totient is φ = 497664.

The previous prime is 644363. The next prime is 644377. The reversal of 644371 is 173446.

644371 = 208² + 209² + ... + 221².

644371 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.

It is a 11-Lehmer number, since φ(644371) divides (644371-1)¹¹.

It is a cyclic number.

It is not a de Polignac number, because 644371 - 2³ = 644363 is a prime.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (644377) by changing a digit.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 6595 + ... + 6691.

It is an arithmetic number, because the mean of its divisors is an integer number (50764).

2⁶⁴⁴³⁷¹ is an apocalyptic number.

644371 is a deficient number, since it is larger than the sum of its proper divisors (167853).

644371 is a wasteful number, since it uses less digits than its factorization.

644371 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 190.

The product of its digits is 2016, while the sum is 25.

The square root of 644371 is about 802.7272263976. The cubic root of 644371 is about 86.3731308625.

The spelling of 644371 in words is "six hundred forty-four thousand, three hundred seventy-one".