516561441554581 has 2 divisors, whose sum is σ = 516561441554582. Its totient is φ = 516561441554580.

The previous prime is 516561441554579. The next prime is 516561441554701. The reversal of 516561441554581 is 185455144165615.

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., 516337910224900 + 223531329681 = 22723070^2 + 472791^2 .

It is a cyclic number.

It is not a de Polignac number, because 516561441554581 - 2¹ = 516561441554579 is a prime.

It is a super-2 number, since 2×516561441554581² (a number of 30 digits) contains 22 as substring.

Together with 516561441554579, it forms a pair of twin primes.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (516561441524581) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 258280720777290 + 258280720777291.

It is an arithmetic number, because the mean of its divisors is an integer number (258280720777291).

Almost surely, 2^{516561441554581} is an apocalyptic number.

It is an amenable number.

516561441554581 is a deficient number, since it is larger than the sum of its proper divisors (1).

516561441554581 is an equidigital number, since it uses as much as digits as its factorization.

516561441554581 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 57600000, while the sum is 61.

The spelling of 516561441554581 in words is "five hundred sixteen trillion, five hundred sixty-one billion, four hundred forty-one million, five hundred fifty-four thousand, five hundred eighty-one".