21343215133621 has 2 divisors, whose sum is σ = 21343215133622. Its totient is φ = 21343215133620.

The previous prime is 21343215133561. The next prime is 21343215133673. The reversal of 21343215133621 is 12633151234312.

It is a happy number.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 18381670138225 + 2961544995396 = 4287385^2 + 1720914^2 .

It is a cyclic number.

It is not a de Polignac number, because 21343215133621 - 2⁹ = 21343215133109 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (21343215133321) 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, 10671607566810 + 10671607566811.

It is an arithmetic number, because the mean of its divisors is an integer number (10671607566811).

Almost surely, 2^{21343215133621} is an apocalyptic number.

It is an amenable number.

21343215133621 is a deficient number, since it is larger than the sum of its proper divisors (1).

21343215133621 is an equidigital number, since it uses as much as digits as its factorization.

21343215133621 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 77760, while the sum is 37.

Adding to 21343215133621 its reverse (12633151234312), we get a palindrome (33976366367933).

The spelling of 21343215133621 in words is "twenty-one trillion, three hundred forty-three billion, two hundred fifteen million, one hundred thirty-three thousand, six hundred twenty-one".