81091112 has 16 divisors (see below), whose sum is σ = 155754900. Its totient is φ = 39556480.

The previous prime is 81091099. The next prime is 81091141. The reversal of 81091112 is 21119018.

It can be written as a sum of positive squares in 2 ways, for example, as 59505796 + 21585316 = 7714^2 + 4646^2 .

It is an unprimeable number.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 123287 + ... + 123942.

Almost surely, 2^81091112 is an apocalyptic number.

81091112 is a gapful number since it is divisible by the number (82) formed by its first and last digit.

It is an amenable number.

81091112 is a deficient number, since it is larger than the sum of its proper divisors (74663788).

81091112 is a wasteful number, since it uses less digits than its factorization.

81091112 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 247276 (or 247272 counting only the distinct ones).

The product of its (nonzero) digits is 144, while the sum is 23.

The square root of 81091112 is about 9005.0603551559. The cubic root of 81091112 is about 432.8370402321.

The spelling of 81091112 in words is "eighty-one million, ninety-one thousand, one hundred twelve".