644597 has 2 divisors, whose sum is σ = 644598. Its totient is φ = 644596.

The previous prime is 644593. The next prime is 644599. The reversal of 644597 is 795446.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 630436 + 14161 = 794^2 + 119^2 .

It is a cyclic number.

It is not a de Polignac number, because 644597 - 2² = 644593 is a prime.

Together with 644599, it forms a pair of twin primes.

It is a Chen prime.

It is a d-powerful number, because it can be written as 6⁷ + 4⁵ + 5⁷ + 4⁹ + 9⁴ + 7⁵ .

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (644593) 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 as a sum of consecutive naturals, namely, 322298 + 322299.

It is an arithmetic number, because the mean of its divisors is an integer number (322299).

2⁶⁴⁴⁵⁹⁷ is an apocalyptic number.

It is an amenable number.

644597 is a deficient number, since it is larger than the sum of its proper divisors (1).

644597 is an equidigital number, since it uses as much as digits as its factorization.

644597 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 30240, while the sum is 35.

The square root of 644597 is about 802.8679841668. The cubic root of 644597 is about 86.3832275542.

The spelling of 644597 in words is "six hundred forty-four thousand, five hundred ninety-seven".