216391317 has 32 divisors (see below), whose sum is σ = 314979840. Its totient is φ = 131604480.

The previous prime is 216391313. The next prime is 216391327. The reversal of 216391317 is 713193612.

It is not a de Polignac number, because 216391317 - 2² = 216391313 is a prime.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (216391313) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written in 31 ways as a sum of consecutive naturals, for example, 499533 + ... + 499965.

It is an arithmetic number, because the mean of its divisors is an integer number (9843120).

Almost surely, 2^216391317 is an apocalyptic number.

It is an amenable number.

216391317 is a deficient number, since it is larger than the sum of its proper divisors (98588523).

216391317 is a wasteful number, since it uses less digits than its factorization.

216391317 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 733.

The product of its digits is 6804, while the sum is 33.

The square root of 216391317 is about 14710.2453072680. The cubic root of 216391317 is about 600.3621119698.

The spelling of 216391317 in words is "two hundred sixteen million, three hundred ninety-one thousand, three hundred seventeen".