644089 has 2 divisors, whose sum is σ = 644090. Its totient is φ = 644088.

The previous prime is 644057. The next prime is 644101. The reversal of 644089 is 980446.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 360000 + 284089 = 600^2 + 533^2 .

It is a cyclic number.

It is not a de Polignac number, because 644089 - 2⁵ = 644057 is a prime.

It is a self number, because there is not a number n which added to its sum of digits gives 644089.

It is not a weakly prime, because it can be changed into another prime (644009) by changing a digit.

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

It is a good prime.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 322044 + 322045.

It is an arithmetic number, because the mean of its divisors is an integer number (322045).

2⁶⁴⁴⁰⁸⁹ is an apocalyptic number.

It is an amenable number.

644089 is a deficient number, since it is larger than the sum of its proper divisors (1).

644089 is an equidigital number, since it uses as much as digits as its factorization.

644089 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 6912, while the sum is 31.

The square root of 644089 is about 802.5515559763. The cubic root of 644089 is about 86.3605290244.

The spelling of 644089 in words is "six hundred forty-four thousand, eighty-nine".