261243175553 has 2 divisors, whose sum is σ = 261243175554. Its totient is φ = 261243175552.

The previous prime is 261243175493. The next prime is 261243175559. The reversal of 261243175553 is 355571342162.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 188727687184 + 72515488369 = 434428^2 + 269287^2 .

It is a cyclic number.

It is not a de Polignac number, because 261243175553 - 2¹⁶ = 261243110017 is a prime.

It is not a weakly prime, because it can be changed into another prime (261243175559) 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, 130621587776 + 130621587777.

It is an arithmetic number, because the mean of its divisors is an integer number (130621587777).

Almost surely, 2^261243175553 is an apocalyptic number.

It is an amenable number.

261243175553 is a deficient number, since it is larger than the sum of its proper divisors (1).

261243175553 is an equidigital number, since it uses as much as digits as its factorization.

261243175553 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 756000, while the sum is 44.

The spelling of 261243175553 in words is "two hundred sixty-one billion, two hundred forty-three million, one hundred seventy-five thousand, five hundred fifty-three".