81118229 has 2 divisors, whose sum is σ = 81118230. Its totient is φ = 81118228.

The previous prime is 81118211. The next prime is 81118231. The reversal of 81118229 is 92281118.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 54316900 + 26801329 = 7370^2 + 5177^2 .

It is a cyclic number.

It is not a de Polignac number, because 81118229 - 2¹² = 81114133 is a prime.

Together with 81118231, it forms a pair of twin primes.

It is a Chen prime.

It is a junction number, because it is equal to n+sod(n) for n = 81118195 and 81118204.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (81111229) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 40559114 + 40559115.

It is an arithmetic number, because the mean of its divisors is an integer number (40559115).

Almost surely, 2^81118229 is an apocalyptic number.

It is an amenable number.

81118229 is a deficient number, since it is larger than the sum of its proper divisors (1).

81118229 is an equidigital number, since it uses as much as digits as its factorization.

81118229 is an evil number, because the sum of its binary digits is even.

The product of its digits is 2304, while the sum is 32.

The square root of 81118229 is about 9006.5658827324. The cubic root of 81118229 is about 432.8852819923.

The spelling of 81118229 in words is "eighty-one million, one hundred eighteen thousand, two hundred twenty-nine".