81175538144 has 24 divisors (see below), whose sum is σ = 159984234648. Its totient is φ = 40544621440.

The previous prime is 81175538089. The next prime is 81175538149. The reversal of 81175538144 is 44183557118.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (81175538149) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 1317782 + ... + 1378005.

It is an arithmetic number, because the mean of its divisors is an integer number (6666009777).

Almost surely, 2^81175538144 is an apocalyptic number.

It is an amenable number.

81175538144 is a deficient number, since it is larger than the sum of its proper divisors (78808696504).

81175538144 is a wasteful number, since it uses less digits than its factorization.

81175538144 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 2696738 (or 2696730 counting only the distinct ones).

The product of its digits is 537600, while the sum is 47.

The spelling of 81175538144 in words is "eighty-one billion, one hundred seventy-five million, five hundred thirty-eight thousand, one hundred forty-four".