261575720689 has 2 divisors, whose sum is σ = 261575720690. Its totient is φ = 261575720688.

The previous prime is 261575720647. The next prime is 261575720699. The reversal of 261575720689 is 986027575162.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 260712360000 + 863360689 = 510600^2 + 29383^2 .

It is a cyclic number.

It is not a de Polignac number, because 261575720689 - 2¹⁵ = 261575687921 is a prime.

It is not a weakly prime, because it can be changed into another prime (261575720699) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 130787860344 + 130787860345.

It is an arithmetic number, because the mean of its divisors is an integer number (130787860345).

Almost surely, 2^261575720689 is an apocalyptic number.

It is an amenable number.

261575720689 is a deficient number, since it is larger than the sum of its proper divisors (1).

261575720689 is an equidigital number, since it uses as much as digits as its factorization.

261575720689 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 12700800, while the sum is 58.

The spelling of 261575720689 in words is "two hundred sixty-one billion, five hundred seventy-five million, seven hundred twenty thousand, six hundred eighty-nine".