216721322165683 has 2 divisors, whose sum is σ = 216721322165684. Its totient is φ = 216721322165682.

The previous prime is 216721322165681. The next prime is 216721322165687. The reversal of 216721322165683 is 386561223127612.

It is a weak prime.

It is a cyclic number.

It is not a de Polignac number, because 216721322165683 - 2¹ = 216721322165681 is a prime.

It is a super-2 number, since 2×216721322165683² (a number of 29 digits) contains 22 as substring.

Together with 216721322165681, it forms a pair of twin primes.

It is not a weakly prime, because it can be changed into another prime (216721322165681) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 108360661082841 + 108360661082842.

It is an arithmetic number, because the mean of its divisors is an integer number (108360661082842).

Almost surely, 2^{216721322165683} is an apocalyptic number.

216721322165683 is a deficient number, since it is larger than the sum of its proper divisors (1).

216721322165683 is an equidigital number, since it uses as much as digits as its factorization.

216721322165683 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 8709120, while the sum is 55.

The spelling of 216721322165683 in words is "two hundred sixteen trillion, seven hundred twenty-one billion, three hundred twenty-two million, one hundred sixty-five thousand, six hundred eighty-three".