21022213 has 2 divisors, whose sum is σ = 21022214. Its totient is φ = 21022212.

The previous prime is 21022193. The next prime is 21022219. The reversal of 21022213 is 31222012.

21022213 is nontrivially palindromic in base 2.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 12623809 + 8398404 = 3553^2 + 2898^2 .

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-21022213 is a prime.

It is equal to p_1331302 and since 21022213 and 1331302 have the same sum of digits, it is a Honaker prime.

It is a junction number, because it is equal to n+sod(n) for n = 21022193 and 21022202.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (21022219) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10511106 + 10511107.

It is an arithmetic number, because the mean of its divisors is an integer number (10511107).

Almost surely, 2^21022213 is an apocalyptic number.

It is an amenable number.

21022213 is a deficient number, since it is larger than the sum of its proper divisors (1).

21022213 is an equidigital number, since it uses as much as digits as its factorization.

21022213 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 48, while the sum is 13.

The square root of 21022213 is about 4584.9986913848. The cubic root of 21022213 is about 275.9896595230.

Adding to 21022213 its reverse (31222012), we get a palindrome (52244225).

The spelling of 21022213 in words is "twenty-one million, twenty-two thousand, two hundred thirteen".