216975816 has 24 divisors (see below), whose sum is σ = 587643030. Its totient is φ = 72325248.

The previous prime is 216975793. The next prime is 216975823. The reversal of 216975816 is 618579612.

216975816 is a `hidden beast` number, since 2 + 1 + 69 + 7 + 581 + 6 = 666.

It can be written as a sum of positive squares in only one way, i.e., 216972900 + 2916 = 14730^2 + 54^2 .

It is a tau number, because it is divible by the number of its divisors (24).

It is an unprimeable number.

It is a polite number, since it can be written in 5 ways as a sum of consecutive naturals, for example, 1506705 + ... + 1506848.

Almost surely, 2^216975816 is an apocalyptic number.

It is an amenable number.

216975816 is an abundant number, since it is smaller than the sum of its proper divisors (370667214).

It is a pseudoperfect number, because it is the sum of a subset of its proper divisors.

216975816 is a wasteful number, since it uses less digits than its factorization.

216975816 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 3013565 (or 3013558 counting only the distinct ones).

The product of its digits is 181440, while the sum is 45.

The square root of 216975816 is about 14730.0989813375. The cubic root of 216975816 is about 600.9021761172.

The spelling of 216975816 in words is "two hundred sixteen million, nine hundred seventy-five thousand, eight hundred sixteen".