216914861 has 2 divisors, whose sum is σ = 216914862. Its totient is φ = 216914860.

The previous prime is 216914837. The next prime is 216914879. The reversal of 216914861 is 168419612.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 179399236 + 37515625 = 13394^2 + 6125^2 .

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-216914861 is a prime.

It is a Sophie Germain prime.

It is a Curzon number.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (216914821) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (19) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 108457430 + 108457431.

It is an arithmetic number, because the mean of its divisors is an integer number (108457431).

Almost surely, 2^216914861 is an apocalyptic number.

It is an amenable number.

216914861 is a deficient number, since it is larger than the sum of its proper divisors (1).

216914861 is an equidigital number, since it uses as much as digits as its factorization.

216914861 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 20736, while the sum is 38.

The square root of 216914861 is about 14728.0297731910. The cubic root of 216914861 is about 600.8459003790.

The spelling of 216914861 in words is "two hundred sixteen million, nine hundred fourteen thousand, eight hundred sixty-one".