81811101 has 8 divisors (see below), whose sum is σ = 109198144. Its totient is φ = 54482400.

The previous prime is 81811097. The next prime is 81811109. The reversal of 81811101 is 10111818.

It is a happy number.

It is a sphenic number, since it is the product of 3 distinct primes.

It is not a de Polignac number, because 81811101 - 2² = 81811097 is a prime.

It is a Duffinian number.

It is a congruent number.

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

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 11200 + ... + 17001.

It is an arithmetic number, because the mean of its divisors is an integer number (13649768).

Almost surely, 2^81811101 is an apocalyptic number.

It is an amenable number.

81811101 is a deficient number, since it is larger than the sum of its proper divisors (27387043).

81811101 is a wasteful number, since it uses less digits than its factorization.

81811101 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 29171.

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

The square root of 81811101 is about 9044.9489219122. The cubic root of 81811101 is about 434.1142871166.

Adding to 81811101 its reverse (10111818), we get a palindrome (91922919).

The spelling of 81811101 in words is "eighty-one million, eight hundred eleven thousand, one hundred one".