21814231 has 2 divisors, whose sum is σ = 21814232. Its totient is φ = 21814230.

The previous prime is 21814229. The next prime is 21814237. The reversal of 21814231 is 13241812.

It is a happy number.

It is a weak prime.

It is a cyclic number.

It is not a de Polignac number, because 21814231 - 2¹ = 21814229 is a prime.

It is a super-2 number, since 2×21814231² = 951721348242722, which contains 22 as substring.

Together with 21814229, it forms a pair of twin primes.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (21814237) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10907115 + 10907116.

It is an arithmetic number, because the mean of its divisors is an integer number (10907116).

Almost surely, 2^21814231 is an apocalyptic number.

21814231 is a deficient number, since it is larger than the sum of its proper divisors (1).

21814231 is an equidigital number, since it uses as much as digits as its factorization.

21814231 is an evil number, because the sum of its binary digits is even.

The product of its digits is 384, while the sum is 22.

The square root of 21814231 is about 4670.5707360022. The cubic root of 21814231 is about 279.4130177798.

The spelling of 21814231 in words is "twenty-one million, eight hundred fourteen thousand, two hundred thirty-one".