261365647 has 2 divisors, whose sum is σ = 261365648. Its totient is φ = 261365646.

The previous prime is 261365639. The next prime is 261365651. The reversal of 261365647 is 746563162.

It is a strong prime.

It is a cyclic number.

It is not a de Polignac number, because 261365647 - 2³ = 261365639 is a prime.

It is a Chen prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (261365617) 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, 130682823 + 130682824.

It is an arithmetic number, because the mean of its divisors is an integer number (130682824).

Almost surely, 2^261365647 is an apocalyptic number.

261365647 is a deficient number, since it is larger than the sum of its proper divisors (1).

261365647 is an equidigital number, since it uses as much as digits as its factorization.

261365647 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 181440, while the sum is 40.

The square root of 261365647 is about 16166.8069512814. The cubic root of 261365647 is about 639.3659467527.

The spelling of 261365647 in words is "two hundred sixty-one million, three hundred sixty-five thousand, six hundred forty-seven".