1085185881 has 12 divisors (see below), whose sum is σ = 1688067108. Its totient is φ = 667806624.

The previous prime is 1085185861. The next prime is 1085185901. The reversal of 1085185881 is 1885815801.

1085185881 is a `hidden beast` number, since 1 + 0 + 8 + 518 + 58 + 81 = 666.

It is an interprime number because it is at equal distance from previous prime (1085185861) and next prime (1085185901).

It can be written as a sum of positive squares in 2 ways, for example, as 55353600 + 1029832281 = 7440^2 + 32091^2 .

It is not a de Polignac number, because 1085185881 - 2¹⁰ = 1085184857 is a prime.

It is a super-2 number, since 2×1085185881² = 2355256792643492322, which contains 22 as substring.

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 (1085185831) 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, 4637430 + ... + 4637663.

It is an arithmetic number, because the mean of its divisors is an integer number (140672259).

Almost surely, 2^1085185881 is an apocalyptic number.

It is an amenable number.

1085185881 is a deficient number, since it is larger than the sum of its proper divisors (602881227).

1085185881 is a wasteful number, since it uses less digits than its factorization.

1085185881 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 9275112 (or 9275109 counting only the distinct ones).

The product of its (nonzero) digits is 102400, while the sum is 45.

The square root of 1085185881 is about 32942.1596286582. The cubic root of 1085185881 is about 1027.6251191163.

It can be divided in two parts, 1085 and 185881, that added together give a triangular number (186966 = T₆₁₁).

The spelling of 1085185881 in words is "one billion, eighty-five million, one hundred eighty-five thousand, eight hundred eighty-one".