261571117 has 2 divisors, whose sum is σ = 261571118. Its totient is φ = 261571116.

The previous prime is 261571049. The next prime is 261571127. The reversal of 261571117 is 711175162.

It is a happy number.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 248819076 + 12752041 = 15774^2 + 3571^2 .

It is a cyclic number.

It is not a de Polignac number, because 261571117 - 2¹⁵ = 261538349 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (261571127) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 130785558 + 130785559.

It is an arithmetic number, because the mean of its divisors is an integer number (130785559).

Almost surely, 2^261571117 is an apocalyptic number.

It is an amenable number.

261571117 is a deficient number, since it is larger than the sum of its proper divisors (1).

261571117 is an equidigital number, since it uses as much as digits as its factorization.

261571117 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 2940, while the sum is 31.

The square root of 261571117 is about 16173.1603899794. The cubic root of 261571117 is about 639.5334465911.

The spelling of 261571117 in words is "two hundred sixty-one million, five hundred seventy-one thousand, one hundred seventeen".