181517449081 has 2 divisors, whose sum is σ = 181517449082. Its totient is φ = 181517449080.

The previous prime is 181517449079. The next prime is 181517449109. The reversal of 181517449081 is 180944715181.

It is a happy number.

181517449081 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 127776936681 + 53740512400 = 357459^2 + 231820^2 .

It is a cyclic number.

It is not a de Polignac number, because 181517449081 - 2¹ = 181517449079 is a prime.

It is a super-2 number, since 2×181517449081² (a number of 23 digits) contains 22 as substring.

Together with 181517449079, it forms a pair of twin primes.

It is not a weakly prime, because it can be changed into another prime (181517449381) 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 as a sum of consecutive naturals, namely, 90758724540 + 90758724541.

It is an arithmetic number, because the mean of its divisors is an integer number (90758724541).

Almost surely, 2^181517449081 is an apocalyptic number.

It is an amenable number.

181517449081 is a deficient number, since it is larger than the sum of its proper divisors (1).

181517449081 is an equidigital number, since it uses as much as digits as its factorization.

181517449081 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 322560, while the sum is 49.

The spelling of 181517449081 in words is "one hundred eighty-one billion, five hundred seventeen million, four hundred forty-nine thousand, eighty-one".