644617 has 2 divisors, whose sum is σ = 644618. Its totient is φ = 644616.

The previous prime is 644599. The next prime is 644629. The reversal of 644617 is 716446.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 594441 + 50176 = 771^2 + 224^2 .

It is a cyclic number.

It is not a de Polignac number, because 644617 - 2⁷ = 644489 is a prime.

644617 is a lucky number.

It is not a weakly prime, because it can be changed into another prime (644647) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 322308 + 322309.

It is an arithmetic number, because the mean of its divisors is an integer number (322309).

2⁶⁴⁴⁶¹⁷ is an apocalyptic number.

It is an amenable number.

644617 is a deficient number, since it is larger than the sum of its proper divisors (1).

644617 is an equidigital number, since it uses as much as digits as its factorization.

644617 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 4032, while the sum is 28.

The square root of 644617 is about 802.8804394180. The cubic root of 644617 is about 86.3841209530.

The spelling of 644617 in words is "six hundred forty-four thousand, six hundred seventeen".