21233213 has 2 divisors, whose sum is σ = 21233214. Its totient is φ = 21233212.

The previous prime is 21233197. The next prime is 21233239. The reversal of 21233213 is 31233212.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 14462809 + 6770404 = 3803^2 + 2602^2 .

It is a cyclic number.

It is not a de Polignac number, because 21233213 - 2⁴ = 21233197 is a prime.

It is a junction number, because it is equal to n+sod(n) for n = 21233191 and 21233200.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (21233243) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10616606 + 10616607.

It is an arithmetic number, because the mean of its divisors is an integer number (10616607).

Almost surely, 2^21233213 is an apocalyptic number.

It is an amenable number.

21233213 is a deficient number, since it is larger than the sum of its proper divisors (1).

21233213 is an equidigital number, since it uses as much as digits as its factorization.

21233213 is an evil number, because the sum of its binary digits is even.

The product of its digits is 216, while the sum is 17.

The square root of 21233213 is about 4607.9510631082. The cubic root of 21233213 is about 276.9099569619.

Adding to 21233213 its reverse (31233212), we get a palindrome (52466425).

Subtracting 21233213 from its reverse (31233212), we obtain a palindrome (9999999).

The spelling of 21233213 in words is "twenty-one million, two hundred thirty-three thousand, two hundred thirteen".