21814186 has 4 divisors (see below), whose sum is σ = 32721282. Its totient is φ = 10907092.

The previous prime is 21814171. The next prime is 21814187. The reversal of 21814186 is 68141812.

It is a semiprime because it is the product of two primes.

It can be written as a sum of positive squares in only one way, i.e., 21669025 + 145161 = 4655^2 + 381^2 .

It is a Smith number, since the sum of its digits (31) coincides with the sum of the digits of its prime factors. Since it is squarefree, it is also a hoax number.

It is not an unprimeable number, because it can be changed into a prime (21814187) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 5453545 + ... + 5453548.

Almost surely, 2^21814186 is an apocalyptic number.

21814186 is a deficient number, since it is larger than the sum of its proper divisors (10907096).

21814186 is a wasteful number, since it uses less digits than its factorization.

21814186 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 10907095.

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

The square root of 21814186 is about 4670.5659186013. The cubic root of 21814186 is about 279.4128256485.

Adding to 21814186 its reverse (68141812), we get a palindrome (89955998).

The spelling of 21814186 in words is "twenty-one million, eight hundred fourteen thousand, one hundred eighty-six".