81167521168 has 20 divisors (see below), whose sum is σ = 157275313200. Its totient is φ = 40580343584.

The previous prime is 81167521163. The next prime is 81167521231. The reversal of 81167521168 is 86112576118.

It is not an unprimeable number, because it can be changed into a prime (81167521163) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 11818 + ... + 403081.

It is an arithmetic number, because the mean of its divisors is an integer number (7863765660).

Almost surely, 2^81167521168 is an apocalyptic number.

It is an amenable number.

81167521168 is a deficient number, since it is larger than the sum of its proper divisors (76107792032).

81167521168 is a wasteful number, since it uses less digits than its factorization.

81167521168 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 427134 (or 427128 counting only the distinct ones).

The product of its digits is 161280, while the sum is 46.

It can be divided in two parts, 81 and 167521168, that added together give a square (167521249 = 12943²).

The spelling of 81167521168 in words is "eighty-one billion, one hundred sixty-seven million, five hundred twenty-one thousand, one hundred sixty-eight".