645257 has 2 divisors, whose sum is σ = 645258. Its totient is φ = 645256.

The previous prime is 645233. The next prime is 645313. The reversal of 645257 is 752546.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 606841 + 38416 = 779^2 + 196^2 .

It is a cyclic number.

It is not a de Polignac number, because 645257 - 2¹⁶ = 579721 is a prime.

It is a Chen prime.

It is a d-powerful number, because it can be written as 6 + 4³ + 2¹⁹ + 5³ + 5⁵ + 7⁶ .

It is an inconsummate number, since it does not exist a number n which divided by its sum of digits gives 645257.

It is not a weakly prime, because it can be changed into another prime (645857) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 322628 + 322629.

It is an arithmetic number, because the mean of its divisors is an integer number (322629).

2⁶⁴⁵²⁵⁷ is an apocalyptic number.

It is an amenable number.

645257 is a deficient number, since it is larger than the sum of its proper divisors (1).

645257 is an equidigital number, since it uses as much as digits as its factorization.

645257 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 8400, while the sum is 29.

The square root of 645257 is about 803.2789054868. The cubic root of 645257 is about 86.4126999650.

The spelling of 645257 in words is "six hundred forty-five thousand, two hundred fifty-seven".