8216186661 has 24 divisors (see below), whose sum is σ = 12424251840. Its totient is φ = 5222200896.

The previous prime is 8216186651. The next prime is 8216186681. The reversal of 8216186661 is 1666816128.

8216186661 is digitally balanced in base 3, because in such base it contains all the possibile digits an equal number of times.

It is not a de Polignac number, because 8216186661 - 2⁶ = 8216186597 is a prime.

It is a Curzon number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (8216186611) by changing a digit.

It is a polite number, since it can be written in 23 ways as a sum of consecutive naturals, for example, 1096 + ... + 128193.

It is an arithmetic number, because the mean of its divisors is an integer number (517677160).

Almost surely, 2^8216186661 is an apocalyptic number.

It is an amenable number.

8216186661 is a deficient number, since it is larger than the sum of its proper divisors (4208065179).

8216186661 is a wasteful number, since it uses less digits than its factorization.

8216186661 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 129625 (or 129622 counting only the distinct ones).

The product of its digits is 165888, while the sum is 45.

The square root of 8216186661 is about 90643.1832020478. The cubic root of 8216186661 is about 2017.8556682366.

The spelling of 8216186661 in words is "eight billion, two hundred sixteen million, one hundred eighty-six thousand, six hundred sixty-one".