21423636449 has 2 divisors, whose sum is σ = 21423636450. Its totient is φ = 21423636448.

The previous prime is 21423636413. The next prime is 21423636461. The reversal of 21423636449 is 94463632412.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 19960038400 + 1463598049 = 141280^2 + 38257^2 .

It is a cyclic number.

It is not a de Polignac number, because 21423636449 - 2¹⁶ = 21423570913 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 (21423636149) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (23) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10711818224 + 10711818225.

It is an arithmetic number, because the mean of its divisors is an integer number (10711818225).

Almost surely, 2^21423636449 is an apocalyptic number.

It is an amenable number.

21423636449 is a deficient number, since it is larger than the sum of its proper divisors (1).

21423636449 is an equidigital number, since it uses as much as digits as its factorization.

21423636449 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 746496, while the sum is 44.

The spelling of 21423636449 in words is "twenty-one billion, four hundred twenty-three million, six hundred thirty-six thousand, four hundred forty-nine".