261686489 has 2 divisors, whose sum is σ = 261686490. Its totient is φ = 261686488.

The previous prime is 261686483. The next prime is 261686507. The reversal of 261686489 is 984686162.

It is a happy number.

261686489 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 207590464 + 54096025 = 14408^2 + 7355^2 .

It is a cyclic number.

It is not a de Polignac number, because 261686489 - 2²⁰ = 260637913 is a prime.

It is not a weakly prime, because it can be changed into another prime (261686483) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 130843244 + 130843245.

It is an arithmetic number, because the mean of its divisors is an integer number (130843245).

Almost surely, 2^261686489 is an apocalyptic number.

It is an amenable number.

261686489 is a deficient number, since it is larger than the sum of its proper divisors (1).

261686489 is an equidigital number, since it uses as much as digits as its factorization.

261686489 is an evil number, because the sum of its binary digits is even.

The product of its digits is 995328, while the sum is 50.

The square root of 261686489 is about 16176.7267702709. The cubic root of 261686489 is about 639.6274597837.

The spelling of 261686489 in words is "two hundred sixty-one million, six hundred eighty-six thousand, four hundred eighty-nine".