644546 has 12 divisors (see below), whose sum is σ = 1124838. Its totient is φ = 276192.

The previous prime is 644531. The next prime is 644549. The reversal of 644546 is 645446.

644546 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 only one way, i.e., 354025 + 290521 = 595^2 + 539^2 .

It is a super-2 number, since 2×644546² = 830879092232, which contains 22 as substring.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (644549) by changing a digit.

It is a polite number, since it can be written in 5 ways as a sum of consecutive naturals, for example, 3191 + ... + 3386.

2⁶⁴⁴⁵⁴⁶ is an apocalyptic number.

644546 is a deficient number, since it is larger than the sum of its proper divisors (480292).

644546 is a wasteful number, since it uses less digits than its factorization.

644546 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 6593 (or 6586 counting only the distinct ones).

The product of its digits is 11520, while the sum is 29.

The square root of 644546 is about 802.8362224016. The cubic root of 644546 is about 86.3809493034.

Subtracting 644546 from its reverse (645446), we obtain a square (900 = 30²).

The spelling of 644546 in words is "six hundred forty-four thousand, five hundred forty-six".