261656279 has 2 divisors, whose sum is σ = 261656280. Its totient is φ = 261656278.

The previous prime is 261656249. The next prime is 261656281. The reversal of 261656279 is 972656162.

It is a strong prime.

It is a cyclic number.

It is not a de Polignac number, because 261656279 - 2¹⁶ = 261590743 is a prime.

Together with 261656281, it forms a pair of twin primes.

It is a Chen prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (261656249) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 130828139 + 130828140.

It is an arithmetic number, because the mean of its divisors is an integer number (130828140).

Almost surely, 2^261656279 is an apocalyptic number.

261656279 is a deficient number, since it is larger than the sum of its proper divisors (1).

261656279 is an equidigital number, since it uses as much as digits as its factorization.

261656279 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 272160, while the sum is 44.

The square root of 261656279 is about 16175.7929944717. The cubic root of 261656279 is about 639.6028452290.

The spelling of 261656279 in words is "two hundred sixty-one million, six hundred fifty-six thousand, two hundred seventy-nine".