261555266069 has 2 divisors, whose sum is σ = 261555266070. Its totient is φ = 261555266068.

The previous prime is 261555266039. The next prime is 261555266107. The reversal of 261555266069 is 960662555162.

261555266069 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 228608296900 + 32946969169 = 478130^2 + 181513^2 .

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-261555266069 is a prime.

It is a super-2 number, since 2×261555266069² (a number of 24 digits) contains 22 as substring.

It is a self number, because there is not a number n which added to its sum of digits gives 261555266069.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (261555266029) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (19) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 130777633034 + 130777633035.

It is an arithmetic number, because the mean of its divisors is an integer number (130777633035).

Almost surely, 2^261555266069 is an apocalyptic number.

It is an amenable number.

261555266069 is a deficient number, since it is larger than the sum of its proper divisors (1).

261555266069 is an equidigital number, since it uses as much as digits as its factorization.

261555266069 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 5832000, while the sum is 53.

The spelling of 261555266069 in words is "two hundred sixty-one billion, five hundred fifty-five million, two hundred sixty-six thousand, sixty-nine".