81181011 has 16 divisors (see below), whose sum is σ = 109648800. Its totient is φ = 53422080.

The previous prime is 81181003. The next prime is 81181021. The reversal of 81181011 is 11018118.

It is a happy number.

It is not a de Polignac number, because 81181011 - 2³ = 81181003 is a prime.

It is not an unprimeable number, because it can be changed into a prime (81181021) by changing a digit.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 85801 + ... + 86741.

It is an arithmetic number, because the mean of its divisors is an integer number (6853050).

Almost surely, 2^81181011 is an apocalyptic number.

81181011 is a deficient number, since it is larger than the sum of its proper divisors (28467789).

81181011 is a wasteful number, since it uses less digits than its factorization.

81181011 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1286.

The product of its (nonzero) digits is 64, while the sum is 21.

The square root of 81181011 is about 9010.0505547971. The cubic root of 81181011 is about 432.9969313538.

Adding to 81181011 its reverse (11018118), we get a palindrome (92199129).

The spelling of 81181011 in words is "eighty-one million, one hundred eighty-one thousand, eleven".