21243001229 has 2 divisors, whose sum is σ = 21243001230. Its totient is φ = 21243001228.

The previous prime is 21243001201. The next prime is 21243001279. The reversal of 21243001229 is 92210034212.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 21062716900 + 180284329 = 145130^2 + 13427^2 .

It is a cyclic number.

It is not a de Polignac number, because 21243001229 - 2³² = 16948033933 is a prime.

It is a Sophie Germain prime.

It is a Curzon number.

It is a junction number, because it is equal to n+sod(n) for n = 21243001198 and 21243001207.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (21243001279) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (19) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10621500614 + 10621500615.

It is an arithmetic number, because the mean of its divisors is an integer number (10621500615).

Almost surely, 2^21243001229 is an apocalyptic number.

It is an amenable number.

21243001229 is a deficient number, since it is larger than the sum of its proper divisors (1).

21243001229 is an equidigital number, since it uses as much as digits as its factorization.

21243001229 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 1728, while the sum is 26.

The spelling of 21243001229 in words is "twenty-one billion, two hundred forty-three million, one thousand, two hundred twenty-nine".