644485297 has 2 divisors, whose sum is σ = 644485298. Its totient is φ = 644485296.

The previous prime is 644485279. The next prime is 644485307. The reversal of 644485297 is 792584446.

Together with previous prime (644485279) it forms an Ormiston pair, because they use the same digits, order apart.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 385886736 + 258598561 = 19644^2 + 16081^2 .

It is a cyclic number.

It is not a de Polignac number, because 644485297 - 2²³ = 636096689 is a prime.

It is a super-2 number, since 2×644485297² = 830722596098356418, which contains 22 as substring.

It is a self number, because there is not a number n which added to its sum of digits gives 644485297.

It is not a weakly prime, because it can be changed into another prime (644495297) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 322242648 + 322242649.

It is an arithmetic number, because the mean of its divisors is an integer number (322242649).

Almost surely, 2^644485297 is an apocalyptic number.

It is an amenable number.

644485297 is a deficient number, since it is larger than the sum of its proper divisors (1).

644485297 is an equidigital number, since it uses as much as digits as its factorization.

644485297 is an evil number, because the sum of its binary digits is even.

The product of its digits is 1935360, while the sum is 49.

The square root of 644485297 is about 25386.7149706298. The cubic root of 644485297 is about 863.7823744762.

The spelling of 644485297 in words is "six hundred forty-four million, four hundred eighty-five thousand, two hundred ninety-seven".