81505167012 has 144 divisors (see below), whose sum is σ = 211018429440. Its totient is φ = 26520177600.

The previous prime is 81505167011. The next prime is 81505167083. The reversal of 81505167012 is 21076150518.

81505167012 is a `hidden beast` number, since 81 + 50 + 516 + 7 + 0 + 12 = 666.

It is a Harshad number since it is a multiple of its sum of digits (36).

It is not an unprimeable number, because it can be changed into a prime (81505167011) 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 47 ways as a sum of consecutive naturals, for example, 129167937 + ... + 129168567.

It is an arithmetic number, because the mean of its divisors is an integer number (1465405760).

Almost surely, 2^81505167012 is an apocalyptic number.

It is an amenable number.

It is a practical number, because each smaller number is the sum of distinct divisors of 81505167012, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (105509214720).

81505167012 is an abundant number, since it is smaller than the sum of its proper divisors (129513262428).

It is a pseudoperfect number, because it is the sum of a subset of its proper divisors.

81505167012 is a wasteful number, since it uses less digits than its factorization.

81505167012 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1174 (or 1169 counting only the distinct ones).

The product of its (nonzero) digits is 16800, while the sum is 36.

The spelling of 81505167012 in words is "eighty-one billion, five hundred five million, one hundred sixty-seven thousand, twelve".