21222013 has 2 divisors, whose sum is σ = 21222014. Its totient is φ = 21222012.

The previous prime is 21221953. The next prime is 21222023. The reversal of 21222013 is 31022212.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 12089529 + 9132484 = 3477^2 + 3022^2 .

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-21222013 is a prime.

It is a junction number, because it is equal to n+sod(n) for n = 21221984 and 21222002.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (21222023) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10611006 + 10611007.

It is an arithmetic number, because the mean of its divisors is an integer number (10611007).

Almost surely, 2^21222013 is an apocalyptic number.

It is an amenable number.

21222013 is a deficient number, since it is larger than the sum of its proper divisors (1).

21222013 is an equidigital number, since it uses as much as digits as its factorization.

21222013 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 21222013 is about 4606.7356121228. The cubic root of 21222013 is about 276.8612606580.

Adding to 21222013 its reverse (31022212), we get a palindrome (52244225).

The spelling of 21222013 in words is "twenty-one million, two hundred twenty-two thousand, thirteen".