81111111101001 has 32 divisors (see below), whose sum is σ = 124123637760000. Its totient is φ = 52294838515920.

The previous prime is 81111111100913. The next prime is 81111111101051. The reversal of 81111111101001 is 10010111111118.

It is not a de Polignac number, because 81111111101001 - 2¹⁷ = 81111110969929 is a prime.

It is not an unprimeable number, because it can be changed into a prime (81111111101051) 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, 31069201 + ... + 33578526.

It is an arithmetic number, because the mean of its divisors is an integer number (3878863680000).

Almost surely, 2^{81111111101001} is an apocalyptic number.

It is an amenable number.

81111111101001 is a deficient number, since it is larger than the sum of its proper divisors (43012526658999).

81111111101001 is a wasteful number, since it uses less digits than its factorization.

81111111101001 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 64649266 (or 64649260 counting only the distinct ones).

The product of its (nonzero) digits is 8, while the sum is 18.

Adding to 81111111101001 its reverse (10010111111118), we get a palindrome (91121222212119).

The spelling of 81111111101001 in words is "eighty-one trillion, one hundred eleven billion, one hundred eleven million, one hundred one thousand, one".