21814187 has 2 divisors, whose sum is σ = 21814188. Its totient is φ = 21814186.

The previous prime is 21814171. The next prime is 21814229. The reversal of 21814187 is 78141812.

It is a weak prime.

It is a cyclic number.

It is not a de Polignac number, because 21814187 - 2⁴ = 21814171 is a prime.

It is a Chen prime.

It is an alternating number because its digits alternate between even and odd.

It is not a weakly prime, because it can be changed into another prime (21814087) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10907093 + 10907094.

It is an arithmetic number, because the mean of its divisors is an integer number (10907094).

Almost surely, 2^21814187 is an apocalyptic number.

21814187 is a deficient number, since it is larger than the sum of its proper divisors (1).

21814187 is an equidigital number, since it uses as much as digits as its factorization.

21814187 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 3584, while the sum is 32.

The square root of 21814187 is about 4670.5660256547. The cubic root of 21814187 is about 279.4128299181.

Adding to 21814187 its reverse (78141812), we get a palindrome (99955999).

The spelling of 21814187 in words is "twenty-one million, eight hundred fourteen thousand, one hundred eighty-seven".