261179718809 has 2 divisors, whose sum is σ = 261179718810. Its totient is φ = 261179718808.

The previous prime is 261179718749. The next prime is 261179718823. The reversal of 261179718809 is 908817971162.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 216899775625 + 44279943184 = 465725^2 + 210428^2 .

It is a cyclic number.

It is not a de Polignac number, because 261179718809 - 2²⁴ = 261162941593 is a prime.

It is not a weakly prime, because it can be changed into another prime (261179718859) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 130589859404 + 130589859405.

It is an arithmetic number, because the mean of its divisors is an integer number (130589859405).

Almost surely, 2^261179718809 is an apocalyptic number.

It is an amenable number.

261179718809 is a deficient number, since it is larger than the sum of its proper divisors (1).

261179718809 is an equidigital number, since it uses as much as digits as its factorization.

261179718809 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 3048192, while the sum is 59.

The spelling of 261179718809 in words is "two hundred sixty-one billion, one hundred seventy-nine million, seven hundred eighteen thousand, eight hundred nine".