21224633 has 2 divisors, whose sum is σ = 21224634. Its totient is φ = 21224632.

The previous prime is 21224617. The next prime is 21224647. The reversal of 21224633 is 33642212.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 18905104 + 2319529 = 4348^2 + 1523^2 .

It is a cyclic number.

It is not a de Polignac number, because 21224633 - 2⁴ = 21224617 is a prime.

It is a Chen prime.

It is a junction number, because it is equal to n+sod(n) for n = 21224599 and 21224608.

It is not a weakly prime, because it can be changed into another prime (21224933) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10612316 + 10612317.

It is an arithmetic number, because the mean of its divisors is an integer number (10612317).

Almost surely, 2^21224633 is an apocalyptic number.

It is an amenable number.

21224633 is a deficient number, since it is larger than the sum of its proper divisors (1).

21224633 is an equidigital number, since it uses as much as digits as its factorization.

21224633 is an evil number, because the sum of its binary digits is even.

The product of its digits is 1728, while the sum is 23.

The square root of 21224633 is about 4607.0199695682. The cubic root of 21224633 is about 276.8726536497.

Adding to 21224633 its reverse (33642212), we get a palindrome (54866845).

The spelling of 21224633 in words is "twenty-one million, two hundred twenty-four thousand, six hundred thirty-three".