644575 has 24 divisors (see below), whose sum is σ = 892800. Its totient is φ = 459360.

The previous prime is 644569. The next prime is 644593. The reversal of 644575 is 575446.

It is a happy number.

It is not a de Polignac number, because 644575 - 2⁷ = 644447 is a prime.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 23 ways as a sum of consecutive naturals, for example, 10896 + ... + 10954.

It is an arithmetic number, because the mean of its divisors is an integer number (37200).

2⁶⁴⁴⁵⁷⁵ is an apocalyptic number.

644575 is a deficient number, since it is larger than the sum of its proper divisors (248225).

644575 is a wasteful number, since it uses less digits than its factorization.

644575 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 111 (or 106 counting only the distinct ones).

The product of its digits is 16800, while the sum is 31.

The square root of 644575 is about 802.8542831673. The cubic root of 644575 is about 86.3822447941.

The spelling of 644575 in words is "six hundred forty-four thousand, five hundred seventy-five".