216573866 has 4 divisors (see below), whose sum is σ = 324860802. Its totient is φ = 108286932.

The previous prime is 216573857. The next prime is 216573881. The reversal of 216573866 is 668375612.

216573866 is digitally balanced in base 3, because in such base it contains all the possibile digits an equal number of times.

It is a semiprime because it is the product of two primes.

It can be written as a sum of positive squares in only one way, i.e., 119137225 + 97436641 = 10915^2 + 9871^2 .

It is an unprimeable number.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 54143465 + ... + 54143468.

Almost surely, 2^216573866 is an apocalyptic number.

216573866 is a deficient number, since it is larger than the sum of its proper divisors (108286936).

216573866 is a wasteful number, since it uses less digits than its factorization.

216573866 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 108286935.

The product of its digits is 362880, while the sum is 44.

The square root of 216573866 is about 14716.4488243598. The cubic root of 216573866 is about 600.5308875329.

The spelling of 216573866 in words is "two hundred sixteen million, five hundred seventy-three thousand, eight hundred sixty-six".