181436881897 has 4 divisors (see below), whose sum is σ = 181452852180. Its totient is φ = 181420911616.

The previous prime is 181436881859. The next prime is 181436881919. The reversal of 181436881897 is 798188634181.

It is a semiprime because it is the product of two primes, and also an emirpimes, since its reverse is a distinct semiprime: 798188634181 = 85703 ⋅9313427.

It can be written as a sum of positive squares in 2 ways, for example, as 103333959936 + 78102921961 = 321456^2 + 279469^2 .

It is a cyclic number.

It is not a de Polignac number, because 181436881897 - 2¹¹ = 181436879849 is a prime.

It is a super-2 number, since 2×181436881897² (a number of 23 digits) contains 22 as substring.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (181436887897) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (23) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 7968088 + ... + 7990825.

It is an arithmetic number, because the mean of its divisors is an integer number (45363213045).

Almost surely, 2^181436881897 is an apocalyptic number.

It is an amenable number.

181436881897 is a deficient number, since it is larger than the sum of its proper divisors (15970283).

181436881897 is a wasteful number, since it uses less digits than its factorization.

181436881897 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 15970282.

The product of its digits is 18579456, while the sum is 64.

The spelling of 181436881897 in words is "one hundred eighty-one billion, four hundred thirty-six million, eight hundred eighty-one thousand, eight hundred ninety-seven".