81611147231 has 2 divisors, whose sum is σ = 81611147232. Its totient is φ = 81611147230.

The previous prime is 81611147221. The next prime is 81611147237. The reversal of 81611147231 is 13274111618.

It is a strong prime.

It is a cyclic number.

It is not a de Polignac number, because 81611147231 - 2¹⁴ = 81611130847 is a prime.

It is a super-2 number, since 2×81611147231² (a number of 23 digits) contains 22 as substring.

It is a junction number, because it is equal to n+sod(n) for n = 81611147191 and 81611147200.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (81611147237) 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, 40805573615 + 40805573616.

It is an arithmetic number, because the mean of its divisors is an integer number (40805573616).

Almost surely, 2^81611147231 is an apocalyptic number.

81611147231 is a deficient number, since it is larger than the sum of its proper divisors (1).

81611147231 is an equidigital number, since it uses as much as digits as its factorization.

81611147231 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 8064, while the sum is 35.

Adding to 81611147231 its reverse (13274111618), we get a palindrome (94885258849).

The spelling of 81611147231 in words is "eighty-one billion, six hundred eleven million, one hundred forty-seven thousand, two hundred thirty-one".