216686881063949 has 2 divisors, whose sum is σ = 216686881063950. Its totient is φ = 216686881063948.

The previous prime is 216686881063883. The next prime is 216686881063951. The reversal of 216686881063949 is 949360188686612.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 154395088038724 + 62291793025225 = 12425582^2 + 7892515^2 .

It is a cyclic number.

It is not a de Polignac number, because 216686881063949 - 2³⁶ = 216618161587213 is a prime.

Together with 216686881063951, it forms a pair of twin primes.

It is a Chen prime.

It is a self number, because there is not a number n which added to its sum of digits gives 216686881063949.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (216686881066949) 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, 108343440531974 + 108343440531975.

It is an arithmetic number, because the mean of its divisors is an integer number (108343440531975).

Almost surely, 2^{216686881063949} is an apocalyptic number.

It is an amenable number.

216686881063949 is a deficient number, since it is larger than the sum of its proper divisors (1).

216686881063949 is an equidigital number, since it uses as much as digits as its factorization.

216686881063949 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 1289945088, while the sum is 77.

The spelling of 216686881063949 in words is "two hundred sixteen trillion, six hundred eighty-six billion, eight hundred eighty-one million, sixty-three thousand, nine hundred forty-nine".