861111871 has 4 divisors (see below), whose sum is σ = 862297072. Its totient is φ = 859926672.

The previous prime is 861111859. The next prime is 861111883. The reversal of 861111871 is 178111168.

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

It is an interprime number because it is at equal distance from previous prime (861111859) and next prime (861111883).

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-861111871 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 (861111821) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 591510 + ... + 592963.

It is an arithmetic number, because the mean of its divisors is an integer number (215574268).

Almost surely, 2^861111871 is an apocalyptic number.

861111871 is a deficient number, since it is larger than the sum of its proper divisors (1185201).

861111871 is a wasteful number, since it uses less digits than its factorization.

861111871 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1185200.

The product of its digits is 2688, while the sum is 34.

The square root of 861111871 is about 29344.7077170654. The cubic root of 861111871 is about 951.3781920791.

The spelling of 861111871 in words is "eight hundred sixty-one million, one hundred eleven thousand, eight hundred seventy-one".