216189689 has 2 divisors, whose sum is σ = 216189690. Its totient is φ = 216189688.

The previous prime is 216189667. The next prime is 216189709. The reversal of 216189689 is 986981612.

It is a happy number.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 146216464 + 69973225 = 12092^2 + 8365^2 .

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-216189689 is a prime.

It is a Chen prime.

It is not a weakly prime, because it can be changed into another prime (216182689) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 108094844 + 108094845.

It is an arithmetic number, because the mean of its divisors is an integer number (108094845).

Almost surely, 2^216189689 is an apocalyptic number.

It is an amenable number.

216189689 is a deficient number, since it is larger than the sum of its proper divisors (1).

216189689 is an equidigital number, since it uses as much as digits as its factorization.

216189689 is an evil number, because the sum of its binary digits is even.

The product of its digits is 373248, while the sum is 50.

The square root of 216189689 is about 14703.3903913349. The cubic root of 216189689 is about 600.1755865735.

The spelling of 216189689 in words is "two hundred sixteen million, one hundred eighty-nine thousand, six hundred eighty-nine".