216813689 has 2 divisors, whose sum is σ = 216813690. Its totient is φ = 216813688.

The previous prime is 216813677. The next prime is 216813713. The reversal of 216813689 is 986318612.

216813689 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 166616464 + 50197225 = 12908^2 + 7085^2 .

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-216813689 is a prime.

It is equal to p_11956688 and since 216813689 and 11956688 have the same sum of digits, it is a Honaker prime.

It is not a weakly prime, because it can be changed into another prime (216810689) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 108406844 + 108406845.

It is an arithmetic number, because the mean of its divisors is an integer number (108406845).

Almost surely, 2^216813689 is an apocalyptic number.

It is an amenable number.

216813689 is a deficient number, since it is larger than the sum of its proper divisors (1).

216813689 is an equidigital number, since it uses as much as digits as its factorization.

216813689 is an evil number, because the sum of its binary digits is even.

The product of its digits is 124416, while the sum is 44.

The square root of 216813689 is about 14724.5946973083. The cubic root of 216813689 is about 600.7524716569.

The spelling of 216813689 in words is "two hundred sixteen million, eight hundred thirteen thousand, six hundred eighty-nine".