861181191 has 24 divisors (see below), whose sum is σ = 1355770416. Its totient is φ = 523566720.

The previous prime is 861181171. The next prime is 861181199. The reversal of 861181191 is 191181168.

It is not a de Polignac number, because 861181191 - 2⁷ = 861181063 is a prime.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (861181199) by changing a digit.

It is a polite number, since it can be written in 23 ways as a sum of consecutive naturals, for example, 34630 + ... + 54051.

It is an arithmetic number, because the mean of its divisors is an integer number (56490434).

Almost surely, 2^861181191 is an apocalyptic number.

861181191 is a deficient number, since it is larger than the sum of its proper divisors (494589225).

861181191 is a wasteful number, since it uses less digits than its factorization.

861181191 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 88783 (or 88780 counting only the distinct ones).

The product of its digits is 3456, while the sum is 36.

The square root of 861181191 is about 29345.8888262053. Note that the first 4 decimals coincide. The cubic root of 861181191 is about 951.4037202243.

The spelling of 861181191 in words is "eight hundred sixty-one million, one hundred eighty-one thousand, one hundred ninety-one".