81308111 has 2 divisors, whose sum is σ = 81308112. Its totient is φ = 81308110.

The previous prime is 81308089. The next prime is 81308113. The reversal of 81308111 is 11180318.

It is a strong prime.

It is a cyclic number.

It is not a de Polignac number, because 81308111 - 2¹⁸ = 81045967 is a prime.

It is a super-2 number, since 2×81308111² = 13222017828776642, which contains 22 as substring.

Together with 81308113, it forms a pair of twin primes.

It is a Chen prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (81308113) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 40654055 + 40654056.

It is an arithmetic number, because the mean of its divisors is an integer number (40654056).

Almost surely, 2^81308111 is an apocalyptic number.

81308111 is a deficient number, since it is larger than the sum of its proper divisors (1).

81308111 is an equidigital number, since it uses as much as digits as its factorization.

81308111 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 192, while the sum is 23.

The square root of 81308111 is about 9017.1010308192. The cubic root of 81308111 is about 433.2227855415. Note that the first 3 decimals are identical.

Adding to 81308111 its reverse (11180318), we get a palindrome (92488429).

The spelling of 81308111 in words is "eighty-one million, three hundred eight thousand, one hundred eleven".