21224219 has 4 divisors (see below), whose sum is σ = 21492960. Its totient is φ = 20955480.

The previous prime is 21224207. The next prime is 21224249. The reversal of 21224219 is 91242212.

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

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-21224219 is a prime.

It is a super-2 number, since 2×21224219² = 900934944319922, which contains 22 as substring.

It is a Duffinian number.

It is a junction number, because it is equal to n+sod(n) for n = 21224194 and 21224203.

It is not an unprimeable number, because it can be changed into a prime (21224249) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 134252 + ... + 134409.

It is an arithmetic number, because the mean of its divisors is an integer number (5373240).

Almost surely, 2^21224219 is an apocalyptic number.

21224219 is a deficient number, since it is larger than the sum of its proper divisors (268741).

21224219 is an equidigital number, since it uses as much as digits as its factorization.

21224219 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 268740.

The product of its digits is 576, while the sum is 23.

The square root of 21224219 is about 4606.9750379180. The cubic root of 21224219 is about 276.8708534454.

It can be divided in two parts, 2 and 1224219, that added together give a palindrome (1224221).

The spelling of 21224219 in words is "twenty-one million, two hundred twenty-four thousand, two hundred nineteen".