9861661689 has 32 divisors (see below), whose sum is σ = 15207198720. Its totient is φ = 5627620800.

The previous prime is 9861661679. The next prime is 9861661697.

9861661689 is nontrivially palindromic in base 10.

It is not a de Polignac number, because 9861661689 - 2¹⁹ = 9861137401 is a prime.

It is not an unprimeable number, because it can be changed into a prime (9861661609) by changing a digit.

It is a polite number, since it can be written in 31 ways as a sum of consecutive naturals, for example, 92419 + ... + 168120.

It is an arithmetic number, because the mean of its divisors is an integer number (475224960).

Almost surely, 2^9861661689 is an apocalyptic number.

It is an amenable number.

9861661689 is a deficient number, since it is larger than the sum of its proper divisors (5345537031).

9861661689 is a wasteful number, since it uses less digits than its factorization.

9861661689 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 260621.

The product of its digits is 6718464, while the sum is 60.

The square root of 9861661689 is about 99305.8995679511. The cubic root of 9861661689 is about 2144.4538278301.

The spelling of 9861661689 in words is "nine billion, eight hundred sixty-one million, six hundred sixty-one thousand, six hundred eighty-nine".