21144186 has 96 divisors (see below), whose sum is σ = 55978560. Its totient is φ = 5896800.

The previous prime is 21144181. The next prime is 21144187. The reversal of 21144186 is 68144112.

It is a happy number.

21144186 is a `hidden beast` number, since 211 + 441 + 8 + 6 = 666.

It is a Harshad number since it is a multiple of its sum of digits (27).

It is not an unprimeable number, because it can be changed into a prime (21144181) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written in 47 ways as a sum of consecutive naturals, for example, 161341 + ... + 161471.

It is an arithmetic number, because the mean of its divisors is an integer number (583110).

Almost surely, 2^21144186 is an apocalyptic number.

It is a practical number, because each smaller number is the sum of distinct divisors of 21144186, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (27989280).

21144186 is an abundant number, since it is smaller than the sum of its proper divisors (34834374).

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

21144186 is a wasteful number, since it uses less digits than its factorization.

21144186 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 217 (or 204 counting only the distinct ones).

The product of its digits is 1536, while the sum is 27.

The square root of 21144186 is about 4598.2807656775. The cubic root of 21144186 is about 276.5224037820.

Adding to 21144186 its reverse (68144112), we get a palindrome (89288298).

The spelling of 21144186 in words is "twenty-one million, one hundred forty-four thousand, one hundred eighty-six".