645244 has 12 divisors (see below), whose sum is σ = 1141504. Its totient is φ = 319104.

The previous prime is 645233. The next prime is 645257. The reversal of 645244 is 442546.

It is a congruent number.

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 444 + ... + 1219.

2⁶⁴⁵²⁴⁴ is an apocalyptic number.

It is an amenable number.

645244 is a deficient number, since it is larger than the sum of its proper divisors (496260).

645244 is a wasteful number, since it uses less digits than its factorization.

645244 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1764 (or 1762 counting only the distinct ones).

The product of its digits is 3840, while the sum is 25.

The square root of 645244 is about 803.2708136114. The cubic root of 645244 is about 86.4121196419.

The spelling of 645244 in words is "six hundred forty-five thousand, two hundred forty-four".