561605555501 has 2 divisors, whose sum is σ = 561605555502. Its totient is φ = 561605555500.

The previous prime is 561605555477. The next prime is 561605555551. The reversal of 561605555501 is 105555506165.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 526097806276 + 35507749225 = 725326^2 + 188435^2 .

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-561605555501 is a prime.

It is a super-2 number, since 2×561605555501² (a number of 24 digits) contains 22 as substring.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (561605555551) 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, 280802777750 + 280802777751.

It is an arithmetic number, because the mean of its divisors is an integer number (280802777751).

Almost surely, 2^561605555501 is an apocalyptic number.

It is an amenable number.

561605555501 is a deficient number, since it is larger than the sum of its proper divisors (1).

561605555501 is an equidigital number, since it uses as much as digits as its factorization.

561605555501 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 562500, while the sum is 44.

The spelling of 561605555501 in words is "five hundred sixty-one billion, six hundred five million, five hundred fifty-five thousand, five hundred one".