81004011111 has 12 divisors (see below), whose sum is σ = 117016306992. Its totient is φ = 53997821856.

The previous prime is 81004011071. The next prime is 81004011139. The reversal of 81004011111 is 11111040018.

It is a happy number.

It is not a de Polignac number, because 81004011111 - 2²³ = 80995622503 is a prime.

It is a super-2 number, since 2×81004011111² (a number of 23 digits) contains 22 as substring.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (81004011191) by changing a digit.

It is a polite number, since it can be written in 11 ways as a sum of consecutive naturals, for example, 297126 + ... + 500291.

It is an arithmetic number, because the mean of its divisors is an integer number (9751358916).

Almost surely, 2^81004011111 is an apocalyptic number.

81004011111 is a deficient number, since it is larger than the sum of its proper divisors (36012295881).

81004011111 is a wasteful number, since it uses less digits than its factorization.

81004011111 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 808710 (or 808707 counting only the distinct ones).

The product of its (nonzero) digits is 32, while the sum is 18.

Adding to 81004011111 its reverse (11111040018), we get a palindrome (92115051129).

The spelling of 81004011111 in words is "eighty-one billion, four million, eleven thousand, one hundred eleven".