81144444117 has 16 divisors (see below), whose sum is σ = 119245073472. Its totient is φ = 48671454720.

The previous prime is 81144444083. The next prime is 81144444119. The reversal of 81144444117 is 71144444118.

It is not a de Polignac number, because 81144444117 - 2¹² = 81144440021 is a prime.

It is a super-2 number, since 2×81144444117² (a number of 23 digits) contains 22 as substring.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (81144444119) 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, 12671658 + ... + 12678059.

It is an arithmetic number, because the mean of its divisors is an integer number (7452817092).

Almost surely, 2^81144444117 is an apocalyptic number.

It is an amenable number.

81144444117 is a deficient number, since it is larger than the sum of its proper divisors (38100629355).

81144444117 is a wasteful number, since it uses less digits than its factorization.

81144444117 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 25349828.

The product of its digits is 57344, while the sum is 39.

Subtracting from 81144444117 its reverse (71144444118), we obtain a palindrome (9999999999).

The spelling of 81144444117 in words is "eighty-one billion, one hundred forty-four million, four hundred forty-four thousand, one hundred seventeen".