861553943181 has 16 divisors (see below), whose sum is σ = 1300458784320. Its totient is φ = 563532138000.

The previous prime is 861553943171. The next prime is 861553943183. The reversal of 861553943181 is 181349355168.

861553943181 is a `hidden beast` number, since 8 + 6 + 1 + 553 + 9 + 4 + 3 + 1 + 81 = 666.

It is not a de Polignac number, because 861553943181 - 2¹⁰ = 861553942157 is a prime.

It is a super-2 number, since 2×861553943181² (a number of 25 digits) contains 22 as substring.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (861553943183) 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 15 ways as a sum of consecutive naturals, for example, 301030695 + ... + 301033556.

It is an arithmetic number, because the mean of its divisors is an integer number (81278674020).

Almost surely, 2^861553943181 is an apocalyptic number.

It is an amenable number.

861553943181 is a deficient number, since it is larger than the sum of its proper divisors (438904841139).

861553943181 is a wasteful number, since it uses less digits than its factorization.

861553943181 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 602064313 (or 602064307 counting only the distinct ones).

The product of its digits is 3110400, while the sum is 54.

The spelling of 861553943181 in words is "eight hundred sixty-one billion, five hundred fifty-three million, nine hundred forty-three thousand, one hundred eighty-one".