21361229 has 2 divisors, whose sum is σ = 21361230. Its totient is φ = 21361228.

The previous prime is 21361217. The next prime is 21361237. The reversal of 21361229 is 92216312.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 20912329 + 448900 = 4573^2 + 670^2 .

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-21361229 is a prime.

It is a Chen prime.

It is a junction number, because it is equal to n+sod(n) for n = 21361198 and 21361207.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (21361259) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10680614 + 10680615.

It is an arithmetic number, because the mean of its divisors is an integer number (10680615).

Almost surely, 2^21361229 is an apocalyptic number.

It is an amenable number.

21361229 is a deficient number, since it is larger than the sum of its proper divisors (1).

21361229 is an equidigital number, since it uses as much as digits as its factorization.

21361229 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 1296, while the sum is 26.

The square root of 21361229 is about 4621.8209614826. The cubic root of 21361229 is about 277.4653431816.

The spelling of 21361229 in words is "twenty-one million, three hundred sixty-one thousand, two hundred twenty-nine".