861886161 has 12 divisors (see below), whose sum is σ = 1246519092. Its totient is φ = 573865056.

The previous prime is 861886147. The next prime is 861886231. The reversal of 861886161 is 161688168.

It can be written as a sum of positive squares in 2 ways, for example, as 691427025 + 170459136 = 26295^2 + 13056^2 .

It is not a de Polignac number, because 861886161 - 2⁷ = 861886033 is a prime.

It is a Smith number, since the sum of its digits (45) coincides with the sum of the digits of its prime factors.

It is not an unprimeable number, because it can be changed into a prime (861886121) by changing a digit.

It is a polite number, since it can be written in 11 ways as a sum of consecutive naturals, for example, 52906 + ... + 67251.

It is an arithmetic number, because the mean of its divisors is an integer number (103876591).

Almost surely, 2^861886161 is an apocalyptic number.

It is an amenable number.

861886161 is a deficient number, since it is larger than the sum of its proper divisors (384632931).

861886161 is a wasteful number, since it uses less digits than its factorization.

861886161 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 120960 (or 120957 counting only the distinct ones).

The product of its digits is 110592, while the sum is 45.

The square root of 861886161 is about 29357.8977619311. The cubic root of 861886161 is about 951.6632583851.

The spelling of 861886161 in words is "eight hundred sixty-one million, eight hundred eighty-six thousand, one hundred sixty-one".