81811107 has 32 divisors (see below), whose sum is σ = 142272000. Its totient is φ = 45481824.

The previous prime is 81811097. The next prime is 81811109. The reversal of 81811107 is 70111818.

It is not a de Polignac number, because 81811107 - 2¹⁰ = 81810083 is a prime.

It is a Harshad number since it is a multiple of its sum of digits (27).

It is not an unprimeable number, because it can be changed into a prime (81811109) by changing a digit.

It is a polite number, since it can be written in 31 ways as a sum of consecutive naturals, for example, 1144 + ... + 12842.

It is an arithmetic number, because the mean of its divisors is an integer number (4446000).

Almost surely, 2^81811107 is an apocalyptic number.

81811107 is a deficient number, since it is larger than the sum of its proper divisors (60460893).

81811107 is a wasteful number, since it uses less digits than its factorization.

81811107 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 11752 (or 11746 counting only the distinct ones).

The product of its (nonzero) digits is 448, while the sum is 27.

The square root of 81811107 is about 9044.9492535890. The cubic root of 81811107 is about 434.1142977292.

It can be divided in two parts, 81811 and 107, that added together give a palindrome (81918).

The spelling of 81811107 in words is "eighty-one million, eight hundred eleven thousand, one hundred seven".