21243214409 has 2 divisors, whose sum is σ = 21243214410. Its totient is φ = 21243214408.

The previous prime is 21243214403. The next prime is 21243214417. The reversal of 21243214409 is 90441234212.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 15553831225 + 5689383184 = 124715^2 + 75428^2 .

It is a cyclic number.

It is not a de Polignac number, because 21243214409 - 2⁴ = 21243214393 is a prime.

It is a Sophie Germain prime.

It is a Curzon number.

It is not a weakly prime, because it can be changed into another prime (21243214403) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10621607204 + 10621607205.

It is an arithmetic number, because the mean of its divisors is an integer number (10621607205).

Almost surely, 2^21243214409 is an apocalyptic number.

It is an amenable number.

21243214409 is a deficient number, since it is larger than the sum of its proper divisors (1).

21243214409 is an equidigital number, since it uses as much as digits as its factorization.

21243214409 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 13824, while the sum is 32.

The spelling of 21243214409 in words is "twenty-one billion, two hundred forty-three million, two hundred fourteen thousand, four hundred nine".