216304961 has 2 divisors, whose sum is σ = 216304962. Its totient is φ = 216304960.

The previous prime is 216304937. The next prime is 216304993. The reversal of 216304961 is 169403612.

It is an a-pointer prime, because the next prime (216304993) can be obtained adding 216304961 to its sum of digits (32).

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 159769600 + 56535361 = 12640^2 + 7519^2 .

It is a cyclic number.

It is not a de Polignac number, because 216304961 - 2⁶ = 216304897 is a prime.

It is a Sophie Germain prime.

It is a Curzon number.

It is not a weakly prime, because it can be changed into another prime (216304901) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 108152480 + 108152481.

It is an arithmetic number, because the mean of its divisors is an integer number (108152481).

Almost surely, 2^216304961 is an apocalyptic number.

It is an amenable number.

216304961 is a deficient number, since it is larger than the sum of its proper divisors (1).

216304961 is an equidigital number, since it uses as much as digits as its factorization.

216304961 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 7776, while the sum is 32.

The square root of 216304961 is about 14707.3097811938. The cubic root of 216304961 is about 600.2822385112.

The spelling of 216304961 in words is "two hundred sixteen million, three hundred four thousand, nine hundred sixty-one".