216547081 has 2 divisors, whose sum is σ = 216547082. Its totient is φ = 216547080.

The previous prime is 216547073. The next prime is 216547087. The reversal of 216547081 is 180745612.

216547081 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 153884025 + 62663056 = 12405^2 + 7916^2 .

It is a cyclic number.

It is not a de Polignac number, because 216547081 - 2³ = 216547073 is a prime.

It is a super-2 number, since 2×216547081² = 93785276579241122, which contains 22 as substring.

It is not a weakly prime, because it can be changed into another prime (216547087) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 108273540 + 108273541.

It is an arithmetic number, because the mean of its divisors is an integer number (108273541).

Almost surely, 2^216547081 is an apocalyptic number.

It is an amenable number.

216547081 is a deficient number, since it is larger than the sum of its proper divisors (1).

216547081 is an equidigital number, since it uses as much as digits as its factorization.

216547081 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 13440, while the sum is 34.

The square root of 216547081 is about 14715.5387600998. The cubic root of 216547081 is about 600.5061294165.

The spelling of 216547081 in words is "two hundred sixteen million, five hundred forty-seven thousand, eighty-one".