216975281 has 2 divisors, whose sum is σ = 216975282. Its totient is φ = 216975280.

The previous prime is 216975229. The next prime is 216975299. The reversal of 216975281 is 182579612.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 215943025 + 1032256 = 14695^2 + 1016^2 .

It is a cyclic number.

It is not a de Polignac number, because 216975281 - 2⁶ = 216975217 is a prime.

It is a super-2 number, since 2×216975281² = 94156545130057922, which contains 22 as substring.

It is not a weakly prime, because it can be changed into another prime (216975221) 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, 108487640 + 108487641.

It is an arithmetic number, because the mean of its divisors is an integer number (108487641).

Almost surely, 2^216975281 is an apocalyptic number.

It is an amenable number.

216975281 is a deficient number, since it is larger than the sum of its proper divisors (1).

216975281 is an equidigital number, since it uses as much as digits as its factorization.

216975281 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 60480, while the sum is 41.

The square root of 216975281 is about 14730.0808212311. The cubic root of 216975281 is about 600.9016822328.

The spelling of 216975281 in words is "two hundred sixteen million, nine hundred seventy-five thousand, two hundred eighty-one".