644197 has 2 divisors, whose sum is σ = 644198. Its totient is φ = 644196.

The previous prime is 644191. The next prime is 644201. The reversal of 644197 is 791446.

644197 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 329476 + 314721 = 574^2 + 561^2 .

It is a cyclic number.

It is not a de Polignac number, because 644197 - 2¹¹ = 642149 is a prime.

It is a Chen prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (644191) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 322098 + 322099.

It is an arithmetic number, because the mean of its divisors is an integer number (322099).

2⁶⁴⁴¹⁹⁷ is an apocalyptic number.

It is an amenable number.

644197 is a deficient number, since it is larger than the sum of its proper divisors (1).

644197 is an equidigital number, since it uses as much as digits as its factorization.

644197 is an evil number, because the sum of its binary digits is even.

The product of its digits is 6048, while the sum is 31.

The square root of 644197 is about 802.6188385529. The cubic root of 644197 is about 86.3653556948.

It can be divided in two parts, 644 and 197, that added together give a square (841 = 29²).

The spelling of 644197 in words is "six hundred forty-four thousand, one hundred ninety-seven".