21204224407 has 2 divisors, whose sum is σ = 21204224408. Its totient is φ = 21204224406.

The previous prime is 21204224399. The next prime is 21204224413. The reversal of 21204224407 is 70442240212.

It is a strong prime.

It is a cyclic number.

It is not a de Polignac number, because 21204224407 - 2³ = 21204224399 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (21204224477) 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, 10602112203 + 10602112204.

It is an arithmetic number, because the mean of its divisors is an integer number (10602112204).

Almost surely, 2^21204224407 is an apocalyptic number.

21204224407 is a deficient number, since it is larger than the sum of its proper divisors (1).

21204224407 is an equidigital number, since it uses as much as digits as its factorization.

21204224407 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 7168, while the sum is 28.

Adding to 21204224407 its reverse (70442240212), we get a palindrome (91646464619).

The spelling of 21204224407 in words is "twenty-one billion, two hundred four million, two hundred twenty-four thousand, four hundred seven".