644293 has 8 divisors (see below), whose sum is σ = 718200. Its totient is φ = 573888.

The previous prime is 644291. The next prime is 644297. The reversal of 644293 is 392446.

644293 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.

It can be written as a sum of positive squares in 4 ways, for example, as 1089 + 643204 = 33^2 + 802^2 .

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

It is a cyclic number.

It is not a de Polignac number, because 644293 - 2¹ = 644291 is a prime.

It is a super-2 number, since 2×644293² = 830226939698, which contains 22 as substring.

It is an Ulam number.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (644291) 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, 478 + ... + 1231.

It is an arithmetic number, because the mean of its divisors is an integer number (89775).

2⁶⁴⁴²⁹³ is an apocalyptic number.

It is an amenable number.

644293 is a deficient number, since it is larger than the sum of its proper divisors (73907).

644293 is a wasteful number, since it uses less digits than its factorization.

644293 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1751.

The product of its digits is 5184, while the sum is 28.

The square root of 644293 is about 802.6786405530. The cubic root of 644293 is about 86.3696456156.

The spelling of 644293 in words is "six hundred forty-four thousand, two hundred ninety-three".