1861166885 has 8 divisors (see below), whose sum is σ = 2364776856. Its totient is φ = 1401349120.

The previous prime is 1861166873. The next prime is 1861166891. The reversal of 1861166885 is 5886611681.

It can be written as a sum of positive squares in 4 ways, for example, as 692005636 + 1169161249 = 26306^2 + 34193^2 .

It is a sphenic number, since it is the product of 3 distinct primes.

It is not a de Polignac number, because 1861166885 - 2⁶ = 1861166821 is a prime.

It is a Duffinian number.

It is a congruent number.

It is an unprimeable number.

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 7 ways as a sum of consecutive naturals, for example, 10947956 + ... + 10948125.

It is an arithmetic number, because the mean of its divisors is an integer number (295597107).

Almost surely, 2^1861166885 is an apocalyptic number.

It is an amenable number.

1861166885 is a deficient number, since it is larger than the sum of its proper divisors (503609971).

1861166885 is a wasteful number, since it uses less digits than its factorization.

1861166885 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 21896103.

The product of its digits is 552960, while the sum is 50.

The square root of 1861166885 is about 43141.2434336332. The cubic root of 1861166885 is about 1230.0660693353.

The spelling of 1861166885 in words is "one billion, eight hundred sixty-one million, one hundred sixty-six thousand, eight hundred eighty-five".