21814421 has 4 divisors (see below), whose sum is σ = 22518144. Its totient is φ = 21110700.

The previous prime is 21814399. The next prime is 21814433. The reversal of 21814421 is 12441812.

It is a semiprime because it is the product of two primes, and also a Blum integer, because the two primes are equal to 3 mod 4.

It is a cyclic number.

It is not a de Polignac number, because 21814421 - 2⁶ = 21814357 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 (21814021) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 351815 + ... + 351876.

It is an arithmetic number, because the mean of its divisors is an integer number (5629536).

Almost surely, 2^21814421 is an apocalyptic number.

It is an amenable number.

21814421 is a deficient number, since it is larger than the sum of its proper divisors (703723).

21814421 is an equidigital number, since it uses as much as digits as its factorization.

21814421 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 703722.

The product of its digits is 512, while the sum is 23.

The square root of 21814421 is about 4670.5910760845. The cubic root of 21814421 is about 279.4138289983.

It can be divided in two parts, 218 and 14421, that multiplied together give a triangular number (3143778 = T₂₅₀₇).

The spelling of 21814421 in words is "twenty-one million, eight hundred fourteen thousand, four hundred twenty-one".