644199 has 4 divisors (see below), whose sum is σ = 858936. Its totient is φ = 429464.

The previous prime is 644197. The next prime is 644201. The reversal of 644199 is 991446.

It is a semiprime because it is the product of two primes.

It is an interprime number because it is at equal distance from previous prime (644197) and next prime (644201).

It is a cyclic number.

It is not a de Polignac number, because 644199 - 2¹ = 644197 is a prime.

It is a D-number.

644199 is a lucky number.

It is a congruent number.

It is an inconsummate number, since it does not exist a number n which divided by its sum of digits gives 644199.

It is not an unprimeable number, because it can be changed into a prime (644191) by changing a digit.

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, 107364 + ... + 107369.

It is an arithmetic number, because the mean of its divisors is an integer number (214734).

2⁶⁴⁴¹⁹⁹ is an apocalyptic number.

644199 is a deficient number, since it is larger than the sum of its proper divisors (214737).

644199 is a wasteful number, since it uses less digits than its factorization.

644199 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 214736.

The product of its digits is 7776, while the sum is 33.

The square root of 644199 is about 802.6200844733. The cubic root of 644199 is about 86.3654450725.

The spelling of 644199 in words is "six hundred forty-four thousand, one hundred ninety-nine".