644829 has 4 divisors (see below), whose sum is σ = 859776. Its totient is φ = 429884.

The previous prime is 644801. The next prime is 644837. The reversal of 644829 is 928446.

It is a semiprime because it is the product of two primes, and also a Blum integer, because the two primes are equal to 3 mod 4.

It is a cyclic number.

It is not a de Polignac number, because 644829 - 2⁵ = 644797 is a prime.

It is a D-number.

It is a self number, because there is not a number n which added to its sum of digits gives 644829.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (644869) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 107469 + ... + 107474.

It is an arithmetic number, because the mean of its divisors is an integer number (214944).

2⁶⁴⁴⁸²⁹ is an apocalyptic number.

It is an amenable number.

644829 is a deficient number, since it is larger than the sum of its proper divisors (214947).

644829 is a wasteful number, since it uses less digits than its factorization.

644829 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 214946.

The product of its digits is 13824, while the sum is 33.

The square root of 644829 is about 803.0124532036. The cubic root of 644829 is about 86.3935898451.

The spelling of 644829 in words is "six hundred forty-four thousand, eight hundred twenty-nine".