21216420361069 has 2 divisors, whose sum is σ = 21216420361070. Its totient is φ = 21216420361068.

The previous prime is 21216420361051. The next prime is 21216420361153. The reversal of 21216420361069 is 96016302461212.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 12650186024100 + 8566234336969 = 3556710^2 + 2926813^2 .

It is a cyclic number.

It is not a de Polignac number, because 21216420361069 - 2⁹ = 21216420360557 is a prime.

It is a super-2 number, since 2×21216420361069² (a number of 27 digits) contains 22 as substring.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (21216420361039) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10608210180534 + 10608210180535.

It is an arithmetic number, because the mean of its divisors is an integer number (10608210180535).

Almost surely, 2^{21216420361069} is an apocalyptic number.

It is an amenable number.

21216420361069 is a deficient number, since it is larger than the sum of its proper divisors (1).

21216420361069 is an equidigital number, since it uses as much as digits as its factorization.

21216420361069 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 186624, while the sum is 43.

The spelling of 21216420361069 in words is "twenty-one trillion, two hundred sixteen billion, four hundred twenty million, three hundred sixty-one thousand, sixty-nine".