21363341666021 has 4 divisors (see below), whose sum is σ = 21363374576172. Its totient is φ = 21363308755872.

The previous prime is 21363341665999. The next prime is 21363341666039. The reversal of 21363341666021 is 12066614336312.

It is a semiprime because it is the product of two primes.

It can be written as a sum of positive squares in 2 ways, for example, as 7498040445025 + 13865301220996 = 2738255^2 + 3723614^2 .

It is a cyclic number.

It is not a de Polignac number, because 21363341666021 - 2¹⁰ = 21363341664997 is a prime.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21363341666071) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 15461360 + ... + 16786313.

It is an arithmetic number, because the mean of its divisors is an integer number (5340843644043).

Almost surely, 2^{21363341666021} is an apocalyptic number.

It is an amenable number.

21363341666021 is a deficient number, since it is larger than the sum of its proper divisors (32910151).

21363341666021 is an equidigital number, since it uses as much as digits as its factorization.

21363341666021 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 32910150.

The product of its (nonzero) digits is 559872, while the sum is 44.

The spelling of 21363341666021 in words is "twenty-one trillion, three hundred sixty-three billion, three hundred forty-one million, six hundred sixty-six thousand, twenty-one".