216784417 has 2 divisors, whose sum is σ = 216784418. Its totient is φ = 216784416.

The previous prime is 216784327. The next prime is 216784439. The reversal of 216784417 is 714487612.

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., 167728401 + 49056016 = 12951^2 + 7004^2 .

It is a cyclic number.

It is not a de Polignac number, because 216784417 - 2²⁷ = 82566689 is a prime.

It is a self number, because there is not a number n which added to its sum of digits gives 216784417.

It is not a weakly prime, because it can be changed into another prime (216784487) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 108392208 + 108392209.

It is an arithmetic number, because the mean of its divisors is an integer number (108392209).

Almost surely, 2^216784417 is an apocalyptic number.

It is an amenable number.

216784417 is a deficient number, since it is larger than the sum of its proper divisors (1).

216784417 is an equidigital number, since it uses as much as digits as its factorization.

216784417 is an evil number, because the sum of its binary digits is even.

The product of its digits is 75264, while the sum is 40.

The square root of 216784417 is about 14723.6006805401. The cubic root of 216784417 is about 600.7254345913.

The spelling of 216784417 in words is "two hundred sixteen million, seven hundred eighty-four thousand, four hundred seventeen".