261686371 has 2 divisors, whose sum is σ = 261686372. Its totient is φ = 261686370.

The previous prime is 261686363. The next prime is 261686413. The reversal of 261686371 is 173686162.

It is a happy number.

It is a weak prime.

It is a cyclic number.

It is not a de Polignac number, because 261686371 - 2³ = 261686363 is a prime.

It is not a weakly prime, because it can be changed into another prime (261686071) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 130843185 + 130843186.

It is an arithmetic number, because the mean of its divisors is an integer number (130843186).

Almost surely, 2^261686371 is an apocalyptic number.

261686371 is a deficient number, since it is larger than the sum of its proper divisors (1).

261686371 is an equidigital number, since it uses as much as digits as its factorization.

261686371 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 72576, while the sum is 40.

The square root of 261686371 is about 16176.7231230555. The cubic root of 261686371 is about 639.6273636431.

The spelling of 261686371 in words is "two hundred sixty-one million, six hundred eighty-six thousand, three hundred seventy-one".