81100221221011 has 2 divisors, whose sum is σ = 81100221221012. Its totient is φ = 81100221221010.

The previous prime is 81100221221003. The next prime is 81100221221059. The reversal of 81100221221011 is 11012212200118.

It is a happy number.

It is a weak prime.

It is a cyclic number.

It is not a de Polignac number, because 81100221221011 - 2³ = 81100221221003 is a prime.

It is a super-3 number, since 3×81100221221011³ (a number of 43 digits) contains 333 as substring.

It is not a weakly prime, because it can be changed into another prime (81100221221111) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 40550110610505 + 40550110610506.

It is an arithmetic number, because the mean of its divisors is an integer number (40550110610506).

Almost surely, 2^{81100221221011} is an apocalyptic number.

81100221221011 is a deficient number, since it is larger than the sum of its proper divisors (1).

81100221221011 is an equidigital number, since it uses as much as digits as its factorization.

81100221221011 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 128, while the sum is 22.

Adding to 81100221221011 its reverse (11012212200118), we get a palindrome (92112433421129).

The spelling of 81100221221011 in words is "eighty-one trillion, one hundred billion, two hundred twenty-one million, two hundred twenty-one thousand, eleven".