261728935609 has 2 divisors, whose sum is σ = 261728935610. Its totient is φ = 261728935608.

The previous prime is 261728935607. The next prime is 261728935667. The reversal of 261728935609 is 906539827162.

It is an a-pointer prime, because the next prime (261728935667) can be obtained adding 261728935609 to its sum of digits (58).

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 247864579600 + 13864356009 = 497860^2 + 117747^2 .

It is a cyclic number.

It is not a de Polignac number, because 261728935609 - 2¹ = 261728935607 is a prime.

Together with 261728935607, it forms a pair of twin primes.

It is not a weakly prime, because it can be changed into another prime (261728935607) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 130864467804 + 130864467805.

It is an arithmetic number, because the mean of its divisors is an integer number (130864467805).

Almost surely, 2^261728935609 is an apocalyptic number.

It is an amenable number.

261728935609 is a deficient number, since it is larger than the sum of its proper divisors (1).

261728935609 is an equidigital number, since it uses as much as digits as its factorization.

261728935609 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 9797760, while the sum is 58.

The spelling of 261728935609 in words is "two hundred sixty-one billion, seven hundred twenty-eight million, nine hundred thirty-five thousand, six hundred nine".