861874487191 has 4 divisors (see below), whose sum is σ = 867035412432. Its totient is φ = 856713561952.

The previous prime is 861874487161. The next prime is 861874487207. The reversal of 861874487191 is 191784478168.

It is a semiprime because it is the product of two primes.

It is a cyclic number.

It is not a de Polignac number, because 861874487191 - 2¹⁹ = 861873962903 is a prime.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (861874487161) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 2580462370 + ... + 2580462703.

It is an arithmetic number, because the mean of its divisors is an integer number (216758853108).

Almost surely, 2^861874487191 is an apocalyptic number.

861874487191 is a deficient number, since it is larger than the sum of its proper divisors (5160925241).

861874487191 is a wasteful number, since it uses less digits than its factorization.

861874487191 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 5160925240.

The product of its digits is 21676032, while the sum is 64.

The spelling of 861874487191 in words is "eight hundred sixty-one billion, eight hundred seventy-four million, four hundred eighty-seven thousand, one hundred ninety-one".