216305217 has 24 divisors (see below), whose sum is σ = 320916960. Its totient is φ = 140310720.

The previous prime is 216305213. The next prime is 216305227. The reversal of 216305217 is 712503612.

It is a happy number.

216305217 is a `hidden beast` number, since 2 + 1 + 630 + 5 + 21 + 7 = 666.

It is not a de Polignac number, because 216305217 - 2² = 216305213 is a prime.

It is not an unprimeable number, because it can be changed into a prime (216305213) by changing a digit.

It is a polite number, since it can be written in 23 ways as a sum of consecutive naturals, for example, 227938 + ... + 228884.

It is an arithmetic number, because the mean of its divisors is an integer number (13371540).

Almost surely, 2^216305217 is an apocalyptic number.

It is an amenable number.

216305217 is a deficient number, since it is larger than the sum of its proper divisors (104611743).

216305217 is a wasteful number, since it uses less digits than its factorization.

216305217 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1613 (or 1610 counting only the distinct ones).

The product of its (nonzero) digits is 2520, while the sum is 27.

The square root of 216305217 is about 14707.3184843465. The cubic root of 216305217 is about 600.2824753253.

Adding to 216305217 its reverse (712503612), we get a palindrome (928808829).

The spelling of 216305217 in words is "two hundred sixteen million, three hundred five thousand, two hundred seventeen".