186812221 has 8 divisors (see below), whose sum is σ = 187972344. Its totient is φ = 185656320.

The previous prime is 186812191. The next prime is 186812239. The reversal of 186812221 is 122218681.

186812221 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 4 ways, for example, as 14546596 + 172265625 = 3814^2 + 13125^2 .

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

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-186812221 is a prime.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (186812261) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 136581 + ... + 137941.

It is an arithmetic number, because the mean of its divisors is an integer number (23496543).

Almost surely, 2^186812221 is an apocalyptic number.

It is an amenable number.

186812221 is a deficient number, since it is larger than the sum of its proper divisors (1160123).

186812221 is a wasteful number, since it uses less digits than its factorization.

186812221 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 2111.

The product of its digits is 3072, while the sum is 31.

The square root of 186812221 is about 13667.9267264644. The cubic root of 186812221 is about 571.6564323501.

It can be divided in two parts, 18681 and 2221, that added together give a palindrome (20902).

The spelling of 186812221 in words is "one hundred eighty-six million, eight hundred twelve thousand, two hundred twenty-one".