261088889 has 2 divisors, whose sum is σ = 261088890. Its totient is φ = 261088888.

The previous prime is 261088871. The next prime is 261088897. The reversal of 261088889 is 988880162.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 243516025 + 17572864 = 15605^2 + 4192^2 .

It is a cyclic number.

It is not a de Polignac number, because 261088889 - 2¹⁶ = 261023353 is a prime.

It is not a weakly prime, because it can be changed into another prime (261088859) 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, 130544444 + 130544445.

It is an arithmetic number, because the mean of its divisors is an integer number (130544445).

Almost surely, 2^261088889 is an apocalyptic number.

It is an amenable number.

261088889 is a deficient number, since it is larger than the sum of its proper divisors (1).

261088889 is an equidigital number, since it uses as much as digits as its factorization.

261088889 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 442368, while the sum is 50.

The square root of 261088889 is about 16158.2452326978. The cubic root of 261088889 is about 639.1401938833.

The spelling of 261088889 in words is "two hundred sixty-one million, eighty-eight thousand, eight hundred eighty-nine".