505404521561 has 2 divisors, whose sum is σ = 505404521562. Its totient is φ = 505404521560.

The previous prime is 505404521537. The next prime is 505404521569. The reversal of 505404521561 is 165125404505.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 488784155161 + 16620366400 = 699131^2 + 128920^2 .

It is a cyclic number.

It is not a de Polignac number, because 505404521561 - 2³⁰ = 504330779737 is a prime.

It is not a weakly prime, because it can be changed into another prime (505404521569) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (23) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 252702260780 + 252702260781.

It is an arithmetic number, because the mean of its divisors is an integer number (252702260781).

Almost surely, 2^505404521561 is an apocalyptic number.

It is an amenable number.

505404521561 is a deficient number, since it is larger than the sum of its proper divisors (1).

505404521561 is an equidigital number, since it uses as much as digits as its factorization.

505404521561 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 120000, while the sum is 38.

The spelling of 505404521561 in words is "five hundred five billion, four hundred four million, five hundred twenty-one thousand, five hundred sixty-one".