644797 has 2 divisors, whose sum is σ = 644798. Its totient is φ = 644796.

The previous prime is 644789. The next prime is 644801. The reversal of 644797 is 797446.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 343396 + 301401 = 586^2 + 549^2 .

It is a cyclic number.

It is not a de Polignac number, because 644797 - 2³ = 644789 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (644717) 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, 322398 + 322399.

It is an arithmetic number, because the mean of its divisors is an integer number (322399).

2⁶⁴⁴⁷⁹⁷ is an apocalyptic number.

It is an amenable number.

644797 is a deficient number, since it is larger than the sum of its proper divisors (1).

644797 is an equidigital number, since it uses as much as digits as its factorization.

644797 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 42336, while the sum is 37.

The square root of 644797 is about 802.9925279852. The cubic root of 644797 is about 86.3921607114.

It can be divided in two parts, 644 and 797, that added together give a palindrome (1441).

The spelling of 644797 in words is "six hundred forty-four thousand, seven hundred ninety-seven".