261241609 has 2 divisors, whose sum is σ = 261241610. Its totient is φ = 261241608.

The previous prime is 261241573. The next prime is 261241633. The reversal of 261241609 is 906142162.

261241609 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 249545209 + 11696400 = 15797^2 + 3420^2 .

It is a cyclic number.

It is not a de Polignac number, because 261241609 - 2¹⁵ = 261208841 is a prime.

It is not a weakly prime, because it can be changed into another prime (261241639) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 130620804 + 130620805.

It is an arithmetic number, because the mean of its divisors is an integer number (130620805).

Almost surely, 2^261241609 is an apocalyptic number.

It is an amenable number.

261241609 is a deficient number, since it is larger than the sum of its proper divisors (1).

261241609 is an equidigital number, since it uses as much as digits as its factorization.

261241609 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 5184, while the sum is 31.

The square root of 261241609 is about 16162.9703025156. The cubic root of 261241609 is about 639.2647880592.

The spelling of 261241609 in words is "two hundred sixty-one million, two hundred forty-one thousand, six hundred nine".