261568243 has 2 divisors, whose sum is σ = 261568244. Its totient is φ = 261568242.

The previous prime is 261568217. The next prime is 261568249. The reversal of 261568243 is 342865162.

It is a strong prime.

It is a cyclic number.

It is not a de Polignac number, because 261568243 - 2⁹ = 261567731 is a prime.

It is a super-2 number, since 2×261568243² = 136835891492214098, which contains 22 as substring.

It is equal to p_14276935 and since 261568243 and 14276935 have the same sum of digits, it is a Honaker prime.

It is not a weakly prime, because it can be changed into another prime (261568249) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (19) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 130784121 + 130784122.

It is an arithmetic number, because the mean of its divisors is an integer number (130784122).

Almost surely, 2^261568243 is an apocalyptic number.

261568243 is a deficient number, since it is larger than the sum of its proper divisors (1).

261568243 is an equidigital number, since it uses as much as digits as its factorization.

261568243 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 69120, while the sum is 37.

The square root of 261568243 is about 16173.0715388265. The cubic root of 261568243 is about 639.5311043016.

The spelling of 261568243 in words is "two hundred sixty-one million, five hundred sixty-eight thousand, two hundred forty-three".