81269266361 has 2 divisors, whose sum is σ = 81269266362. Its totient is φ = 81269266360.

The previous prime is 81269266339. The next prime is 81269266363. The reversal of 81269266361 is 16366296218.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 68549712400 + 12719553961 = 261820^2 + 112781^2 .

It is a cyclic number.

It is not a de Polignac number, because 81269266361 - 2¹⁴ = 81269249977 is a prime.

Together with 81269266363, it forms a pair of twin primes.

It is a Chen prime.

It is not a weakly prime, because it can be changed into another prime (81269266363) 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, 40634633180 + 40634633181.

It is an arithmetic number, because the mean of its divisors is an integer number (40634633181).

Almost surely, 2^81269266361 is an apocalyptic number.

It is an amenable number.

81269266361 is a deficient number, since it is larger than the sum of its proper divisors (1).

81269266361 is an equidigital number, since it uses as much as digits as its factorization.

81269266361 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 1119744, while the sum is 50.

The spelling of 81269266361 in words is "eighty-one billion, two hundred sixty-nine million, two hundred sixty-six thousand, three hundred sixty-one".