261816271 has 2 divisors, whose sum is σ = 261816272. Its totient is φ = 261816270.

The previous prime is 261816253. The next prime is 261816277. The reversal of 261816271 is 172618162.

It is a strong prime.

It is a cyclic number.

It is not a de Polignac number, because 261816271 - 2²⁷ = 127598543 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (261816277) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 130908135 + 130908136.

It is an arithmetic number, because the mean of its divisors is an integer number (130908136).

Almost surely, 2^261816271 is an apocalyptic number.

261816271 is a deficient number, since it is larger than the sum of its proper divisors (1).

261816271 is an equidigital number, since it uses as much as digits as its factorization.

261816271 is an evil number, because the sum of its binary digits is even.

The product of its digits is 8064, while the sum is 34.

The square root of 261816271 is about 16180.7376531480. The cubic root of 261816271 is about 639.7331822354.

The spelling of 261816271 in words is "two hundred sixty-one million, eight hundred sixteen thousand, two hundred seventy-one".