261889211 has 2 divisors, whose sum is σ = 261889212. Its totient is φ = 261889210.

The previous prime is 261889207. The next prime is 261889213. The reversal of 261889211 is 112988162.

It is a strong prime.

It is a cyclic number.

It is not a de Polignac number, because 261889211 - 2² = 261889207 is a prime.

Together with 261889213, it forms a pair of twin primes.

It is a Chen prime.

It is not a weakly prime, because it can be changed into another prime (261889213) 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, 130944605 + 130944606.

It is an arithmetic number, because the mean of its divisors is an integer number (130944606).

Almost surely, 2^261889211 is an apocalyptic number.

261889211 is a deficient number, since it is larger than the sum of its proper divisors (1).

261889211 is an equidigital number, since it uses as much as digits as its factorization.

261889211 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 13824, while the sum is 38.

The square root of 261889211 is about 16182.9914107374. The cubic root of 261889211 is about 639.7925849679.

The spelling of 261889211 in words is "two hundred sixty-one million, eight hundred eighty-nine thousand, two hundred eleven".