181321326729 has 6 divisors (see below), whose sum is σ = 261908583066. Its totient is φ = 120880884480.

The previous prime is 181321326707. The next prime is 181321326731. The reversal of 181321326729 is 927623123181.

It is a happy number.

181321326729 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.

It can be written as a sum of positive squares in only one way, i.e., 117393261129 + 63928065600 = 342627^2 + 252840^2 .

It is not a de Polignac number, because 181321326729 - 2⁷ = 181321326601 is a prime.

It is a Curzon number.

It is not an unprimeable number, because it can be changed into a prime (181321326029) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (19) of ones.

It is a polite number, since it can be written in 5 ways as a sum of consecutive naturals, for example, 10073407032 + ... + 10073407049.

It is an arithmetic number, because the mean of its divisors is an integer number (43651430511).

Almost surely, 2^181321326729 is an apocalyptic number.

It is an amenable number.

181321326729 is a deficient number, since it is larger than the sum of its proper divisors (80587256337).

181321326729 is a wasteful number, since it uses less digits than its factorization.

181321326729 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 20146814087 (or 20146814084 counting only the distinct ones).

The product of its digits is 217728, while the sum is 45.

The spelling of 181321326729 in words is "one hundred eighty-one billion, three hundred twenty-one million, three hundred twenty-six thousand, seven hundred twenty-nine".