206645281 has 2 divisors, whose sum is σ = 206645282. Its totient is φ = 206645280.

The previous prime is 206645279. The next prime is 206645303. The reversal of 206645281 is 182546602.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 204347025 + 2298256 = 14295^2 + 1516^2 .

It is a cyclic number.

It is not a de Polignac number, because 206645281 - 2¹ = 206645279 is a prime.

It is a super-2 number, since 2×206645281² = 85404544319137922, which contains 22 as substring.

Together with 206645279, it forms a pair of twin primes.

It is not a weakly prime, because it can be changed into another prime (206640281) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 103322640 + 103322641.

It is an arithmetic number, because the mean of its divisors is an integer number (103322641).

Almost surely, 2^206645281 is an apocalyptic number.

It is an amenable number.

206645281 is a deficient number, since it is larger than the sum of its proper divisors (1).

206645281 is an equidigital number, since it uses as much as digits as its factorization.

206645281 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 23040, while the sum is 34.

The square root of 206645281 is about 14375.1619469139. The cubic root of 206645281 is about 591.2100808434.

The spelling of 206645281 in words is "two hundred six million, six hundred forty-five thousand, two hundred eighty-one".