81122811 has 32 divisors (see below), whose sum is σ = 138006528. Its totient is φ = 41156640.

The previous prime is 81122791. The next prime is 81122819. The reversal of 81122811 is 11822118.

It is not a de Polignac number, because 81122811 - 2⁵ = 81122779 is a prime.

It is not an unprimeable number, because it can be changed into a prime (81122819) 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, 5850 + ... + 14016.

It is an arithmetic number, because the mean of its divisors is an integer number (4312704).

Almost surely, 2^81122811 is an apocalyptic number.

81122811 is a deficient number, since it is larger than the sum of its proper divisors (56883717).

81122811 is a wasteful number, since it uses less digits than its factorization.

81122811 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 8231.

The product of its digits is 256, while the sum is 24.

The square root of 81122811 is about 9006.8202491223. The cubic root of 81122811 is about 432.8934324128.

Adding to 81122811 its reverse (11822118), we get a palindrome (92944929).

The spelling of 81122811 in words is "eighty-one million, one hundred twenty-two thousand, eight hundred eleven".