216020081 has 2 divisors, whose sum is σ = 216020082. Its totient is φ = 216020080.

The previous prime is 216020041. The next prime is 216020087. The reversal of 216020081 is 180020612.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 212722225 + 3297856 = 14585^2 + 1816^2 .

It is a cyclic number.

It is not a de Polignac number, because 216020081 - 2⁶ = 216020017 is a prime.

It is a super-2 number, since 2×216020081² = 93329350790493122, which contains 22 as substring.

It is a Sophie Germain prime.

It is a Chen prime.

It is a Curzon number.

It is not a weakly prime, because it can be changed into another prime (216020087) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 108010040 + 108010041.

It is an arithmetic number, because the mean of its divisors is an integer number (108010041).

Almost surely, 2^216020081 is an apocalyptic number.

It is an amenable number.

216020081 is a deficient number, since it is larger than the sum of its proper divisors (1).

216020081 is an equidigital number, since it uses as much as digits as its factorization.

216020081 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 192, while the sum is 20.

The square root of 216020081 is about 14697.6216103151. The cubic root of 216020081 is about 600.0185929424.

Adding to 216020081 its reverse (180020612), we get a palindrome (396040693).

The spelling of 216020081 in words is "two hundred sixteen million, twenty thousand, eighty-one".