81111115 has 16 divisors (see below), whose sum is σ = 103039200. Its totient is φ = 61189632.

The previous prime is 81111101. The next prime is 81111119. The reversal of 81111115 is 51111118.

It is a cyclic number.

It is not a de Polignac number, because 81111115 - 2¹⁹ = 80586827 is a prime.

It is a junction number, because it is equal to n+sod(n) for n = 81111092 and 81111101.

It is not an unprimeable number, because it can be changed into a prime (81111119) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 270 + ... + 12739.

It is an arithmetic number, because the mean of its divisors is an integer number (6439950).

Almost surely, 2^81111115 is an apocalyptic number.

81111115 is a deficient number, since it is larger than the sum of its proper divisors (21928085).

81111115 is a wasteful number, since it uses less digits than its factorization.

81111115 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 13086.

The product of its digits is 40, while the sum is 19.

The square root of 81111115 is about 9006.1709399722. The cubic root of 81111115 is about 432.8726270648.

The spelling of 81111115 in words is "eighty-one million, one hundred eleven thousand, one hundred fifteen".