81222572881 has 2 divisors, whose sum is σ = 81222572882. Its totient is φ = 81222572880.

The previous prime is 81222572863. The next prime is 81222572887. The reversal of 81222572881 is 18827522218.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 80292322881 + 930250000 = 283359^2 + 30500^2 .

It is a cyclic number.

It is not a de Polignac number, because 81222572881 - 2²¹ = 81220475729 is a prime.

It is a super-2 number, since 2×81222572881² (a number of 23 digits) contains 22 as substring.

It is not a weakly prime, because it can be changed into another prime (81222572887) 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, 40611286440 + 40611286441.

It is an arithmetic number, because the mean of its divisors is an integer number (40611286441).

Almost surely, 2^81222572881 is an apocalyptic number.

It is an amenable number.

81222572881 is a deficient number, since it is larger than the sum of its proper divisors (1).

81222572881 is an equidigital number, since it uses as much as digits as its factorization.

81222572881 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 286720, while the sum is 46.

The spelling of 81222572881 in words is "eighty-one billion, two hundred twenty-two million, five hundred seventy-two thousand, eight hundred eighty-one".