999568738081 has 2 divisors, whose sum is σ = 999568738082. Its totient is φ = 999568738080.

The previous prime is 999568738061. The next prime is 999568738093. The reversal of 999568738081 is 180837865999.

999568738081 = T₈₁₆₃₁₉ + T₈₁₆₃₂₀ + T₈₁₆₃₂₁.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 913775399056 + 85793339025 = 955916^2 + 292905^2 .

It is a cyclic number.

It is not a de Polignac number, because 999568738081 - 2⁷ = 999568737953 is a prime.

It is a super-2 number, since 2×999568738081² (a number of 25 digits) contains 22 as substring.

It is a junction number, because it is equal to n+sod(n) for n = 999568737995 and 999568738013.

It is not a weakly prime, because it can be changed into another prime (999568738061) 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, 499784369040 + 499784369041.

It is an arithmetic number, because the mean of its divisors is an integer number (499784369041).

Almost surely, 2^999568738081 is an apocalyptic number.

999568738081 is the 816321-st centered triangular number.

It is an amenable number.

999568738081 is a deficient number, since it is larger than the sum of its proper divisors (1).

999568738081 is an equidigital number, since it uses as much as digits as its factorization.

999568738081 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 235146240, while the sum is 73.

The spelling of 999568738081 in words is "nine hundred ninety-nine billion, five hundred sixty-eight million, seven hundred thirty-eight thousand, eighty-one".