9861681636 has 81 divisors (see below), whose sum is σ = 25927895721. Its totient is φ = 3281864688.

The previous prime is 9861681629. The next prime is 9861681677. The reversal of 9861681636 is 6361861689.

The square root of 9861681636 is 99306.

It is a perfect power (a square), and thus also a powerful number.

9861681636 is a `hidden beast` number, since 9 + 8 + 616 + 8 + 16 + 3 + 6 = 666.

9861681636 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.

It can be written as a sum of positive squares in only one way, i.e., 32148900 + 9829532736 = 5670^2 + 99144^2 .

It is a tau number, because it is divible by the number of its divisors (81).

It is a Harshad number since it is a multiple of its sum of digits (54).

It is an unprimeable number.

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 26 ways as a sum of consecutive naturals, for example, 16087266 + ... + 16087878.

Almost surely, 2^9861681636 is an apocalyptic number.

9861681636 is the 99306-th square number.

It is an amenable number.

It is a practical number, because each smaller number is the sum of distinct divisors of 9861681636

9861681636 is an abundant number, since it is smaller than the sum of its proper divisors (16066214085).

It is a pseudoperfect number, because it is the sum of a subset of its proper divisors.

9861681636 is an frugal number, since it uses more digits than its factorization.

9861681636 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1254 (or 618 counting only the distinct ones).

The product of its digits is 2239488, while the sum is 54.

The cubic root of 9861681636 is about 2144.4552736781.

The spelling of 9861681636 in words is "nine billion, eight hundred sixty-one million, six hundred eighty-one thousand, six hundred thirty-six".