81323111 has 2 divisors, whose sum is σ = 81323112. Its totient is φ = 81323110.

The previous prime is 81323089. The next prime is 81323129. The reversal of 81323111 is 11132318.

It is a strong prime.

It is a cyclic number.

It is not a de Polignac number, because 81323111 - 2¹⁴ = 81306727 is a prime.

It is a super-2 number, since 2×81323111² = 13226896765436642, which contains 22 as substring.

It is a Sophie Germain prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (81323171) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 40661555 + 40661556.

It is an arithmetic number, because the mean of its divisors is an integer number (40661556).

Almost surely, 2^81323111 is an apocalyptic number.

81323111 is a deficient number, since it is larger than the sum of its proper divisors (1).

81323111 is an equidigital number, since it uses as much as digits as its factorization.

81323111 is an evil number, because the sum of its binary digits is even.

The product of its digits is 144, while the sum is 20.

The square root of 81323111 is about 9017.9327453691. The cubic root of 81323111 is about 433.2494247133.

Adding to 81323111 its reverse (11132318), we get a palindrome (92455429).

The spelling of 81323111 in words is "eighty-one million, three hundred twenty-three thousand, one hundred eleven".