216915689 has 2 divisors, whose sum is σ = 216915690. Its totient is φ = 216915688.

The previous prime is 216915667. The next prime is 216915701. The reversal of 216915689 is 986519612.

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., 133010089 + 83905600 = 11533^2 + 9160^2 .

It is a cyclic number.

It is not a de Polignac number, because 216915689 - 2²⁴ = 200138473 is a prime.

It is a super-2 number, since 2×216915689² = 94104832268689442, which contains 22 as substring.

It is a Chen prime.

It is not a weakly prime, because it can be changed into another prime (216915659) 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, 108457844 + 108457845.

It is an arithmetic number, because the mean of its divisors is an integer number (108457845).

Almost surely, 2^216915689 is an apocalyptic number.

It is an amenable number.

216915689 is a deficient number, since it is larger than the sum of its proper divisors (1).

216915689 is an equidigital number, since it uses as much as digits as its factorization.

216915689 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 233280, while the sum is 47.

The square root of 216915689 is about 14728.0578828303. The cubic root of 216915689 is about 600.8466648875.

The spelling of 216915689 in words is "two hundred sixteen million, nine hundred fifteen thousand, six hundred eighty-nine".