21238229 has 2 divisors, whose sum is σ = 21238230. Its totient is φ = 21238228.

The previous prime is 21238211. The next prime is 21238249. The reversal of 21238229 is 92283212.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 20268004 + 970225 = 4502^2 + 985^2 .

It is a cyclic number.

It is not a de Polignac number, because 21238229 - 2⁸ = 21237973 is a prime.

It is a Chen prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (21238249) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10619114 + 10619115.

It is an arithmetic number, because the mean of its divisors is an integer number (10619115).

Almost surely, 2^21238229 is an apocalyptic number.

It is an amenable number.

21238229 is a deficient number, since it is larger than the sum of its proper divisors (1).

21238229 is an equidigital number, since it uses as much as digits as its factorization.

21238229 is an evil number, because the sum of its binary digits is even.

The product of its digits is 3456, while the sum is 29.

The square root of 21238229 is about 4608.4953075814. The cubic root of 21238229 is about 276.9317603976.

The spelling of 21238229 in words is "twenty-one million, two hundred thirty-eight thousand, two hundred twenty-nine".