261322291 has 2 divisors, whose sum is σ = 261322292. Its totient is φ = 261322290.

The previous prime is 261322289. The next prime is 261322301. The reversal of 261322291 is 192223162.

It is a weak prime.

It is a cyclic number.

It is not a de Polignac number, because 261322291 - 2¹ = 261322289 is a prime.

Together with 261322289, it forms a pair of twin primes.

It is not a weakly prime, because it can be changed into another prime (261326291) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 130661145 + 130661146.

It is an arithmetic number, because the mean of its divisors is an integer number (130661146).

Almost surely, 2^261322291 is an apocalyptic number.

261322291 is a deficient number, since it is larger than the sum of its proper divisors (1).

261322291 is an equidigital number, since it uses as much as digits as its factorization.

261322291 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 2592, while the sum is 28.

The square root of 261322291 is about 16165.4660000880. The cubic root of 261322291 is about 639.3305915798.

The spelling of 261322291 in words is "two hundred sixty-one million, three hundred twenty-two thousand, two hundred ninety-one".