265544505445561 has 2 divisors, whose sum is σ = 265544505445562. Its totient is φ = 265544505445560.

The previous prime is 265544505445537. The next prime is 265544505445591. The reversal of 265544505445561 is 165544505445562.

It is a happy number.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 151306138030336 + 114238367415225 = 12300656^2 + 10688235^2 .

It is a cyclic number.

It is not a de Polignac number, because 265544505445561 - 2⁷ = 265544505445433 is a prime.

It is a self number, because there is not a number n which added to its sum of digits gives 265544505445561.

It is not a weakly prime, because it can be changed into another prime (265544505445591) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 132772252722780 + 132772252722781.

It is an arithmetic number, because the mean of its divisors is an integer number (132772252722781).

Almost surely, 2^{265544505445561} is an apocalyptic number.

It is an amenable number.

265544505445561 is a deficient number, since it is larger than the sum of its proper divisors (1).

265544505445561 is an equidigital number, since it uses as much as digits as its factorization.

265544505445561 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 288000000, while the sum is 61.

Subtracting from 265544505445561 its reverse (165544505445562), we obtain a palindrome (99999999999999).

The spelling of 265544505445561 in words is "two hundred sixty-five trillion, five hundred forty-four billion, five hundred five million, four hundred forty-five thousand, five hundred sixty-one".