21213566533 has 2 divisors, whose sum is σ = 21213566534. Its totient is φ = 21213566532.

The previous prime is 21213566527. The next prime is 21213566567. The reversal of 21213566533 is 33566531212.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 17720401924 + 3493164609 = 133118^2 + 59103^2 .

It is a cyclic number.

It is not a de Polignac number, because 21213566533 - 2⁹ = 21213566021 is a prime.

It is a junction number, because it is equal to n+sod(n) for n = 21213566492 and 21213566501.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (21213563533) 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, 10606783266 + 10606783267.

It is an arithmetic number, because the mean of its divisors is an integer number (10606783267).

Almost surely, 2^21213566533 is an apocalyptic number.

It is an amenable number.

21213566533 is a deficient number, since it is larger than the sum of its proper divisors (1).

21213566533 is an equidigital number, since it uses as much as digits as its factorization.

21213566533 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 97200, while the sum is 37.

The spelling of 21213566533 in words is "twenty-one billion, two hundred thirteen million, five hundred sixty-six thousand, five hundred thirty-three".