505405345561 has 2 divisors, whose sum is σ = 505405345562. Its totient is φ = 505405345560.

The previous prime is 505405345507. The next prime is 505405345567. The reversal of 505405345561 is 165543504505.

It is a happy number.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 388334617225 + 117070728336 = 623165^2 + 342156^2 .

It is a cyclic number.

It is not a de Polignac number, because 505405345561 - 2¹⁵ = 505405312793 is a prime.

It is not a weakly prime, because it can be changed into another prime (505405345567) 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, 252702672780 + 252702672781.

It is an arithmetic number, because the mean of its divisors is an integer number (252702672781).

Almost surely, 2^505405345561 is an apocalyptic number.

It is an amenable number.

505405345561 is a deficient number, since it is larger than the sum of its proper divisors (1).

505405345561 is an equidigital number, since it uses as much as digits as its factorization.

505405345561 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 900000, while the sum is 43.

The spelling of 505405345561 in words is "five hundred five billion, four hundred five million, three hundred forty-five thousand, five hundred sixty-one".