81232413281 has 2 divisors, whose sum is σ = 81232413282. Its totient is φ = 81232413280.

The previous prime is 81232413259. The next prime is 81232413319. The reversal of 81232413281 is 18231423218.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 50947712656 + 30284700625 = 225716^2 + 174025^2 .

It is a cyclic number.

It is not a de Polignac number, because 81232413281 - 2²² = 81228218977 is a prime.

It is a super-2 number, since 2×81232413281² (a number of 23 digits) contains 22 as substring.

It is not a weakly prime, because it can be changed into another prime (81232413181) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 40616206640 + 40616206641.

It is an arithmetic number, because the mean of its divisors is an integer number (40616206641).

Almost surely, 2^81232413281 is an apocalyptic number.

It is an amenable number.

81232413281 is a deficient number, since it is larger than the sum of its proper divisors (1).

81232413281 is an equidigital number, since it uses as much as digits as its factorization.

81232413281 is an evil number, because the sum of its binary digits is even.

The product of its digits is 18432, while the sum is 35.

Adding to 81232413281 its reverse (18231423218), we get a palindrome (99463836499).

The spelling of 81232413281 in words is "eighty-one billion, two hundred thirty-two million, four hundred thirteen thousand, two hundred eighty-one".