216818973 has 18 divisors (see below), whose sum is σ = 364315614. Its totient is φ = 123896304.

The previous prime is 216818963. The next prime is 216818977. The reversal of 216818973 is 379818612.

It can be written as a sum of positive squares in only one way, i.e., 116057529 + 100761444 = 10773^2 + 10038^2 .

It is not a de Polignac number, because 216818973 - 2⁸ = 216818717 is a prime.

It is a Curzon number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (216818977) by changing a digit.

It is a polite number, since it can be written in 17 ways as a sum of consecutive naturals, for example, 245386 + ... + 246267.

Almost surely, 2^216818973 is an apocalyptic number.

It is an amenable number.

216818973 is a deficient number, since it is larger than the sum of its proper divisors (147496641).

216818973 is a wasteful number, since it uses less digits than its factorization.

216818973 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 491673 (or 491663 counting only the distinct ones).

The product of its digits is 145152, while the sum is 45.

The square root of 216818973 is about 14724.7741239042. The cubic root of 216818973 is about 600.7573519611.

The spelling of 216818973 in words is "two hundred sixteen million, eight hundred eighteen thousand, nine hundred seventy-three".