261665577540673 has 2 divisors, whose sum is σ = 261665577540674. Its totient is φ = 261665577540672.

The previous prime is 261665577540613. The next prime is 261665577540701. The reversal of 261665577540673 is 376045775566162.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 258945641036944 + 2719936503729 = 16091788^2 + 1649223^2 .

It is a cyclic number.

It is not a de Polignac number, because 261665577540673 - 2⁹ = 261665577540161 is a prime.

It is not a weakly prime, because it can be changed into another prime (261665577540613) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 130832788770336 + 130832788770337.

It is an arithmetic number, because the mean of its divisors is an integer number (130832788770337).

Almost surely, 2^{261665577540673} is an apocalyptic number.

It is an amenable number.

261665577540673 is a deficient number, since it is larger than the sum of its proper divisors (1).

261665577540673 is an equidigital number, since it uses as much as digits as its factorization.

261665577540673 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 1333584000, while the sum is 70.

The spelling of 261665577540673 in words is "two hundred sixty-one trillion, six hundred sixty-five billion, five hundred seventy-seven million, five hundred forty thousand, six hundred seventy-three".