216581316 has 24 divisors (see below), whose sum is σ = 577550400. Its totient is φ = 61880352.

The previous prime is 216581273. The next prime is 216581327. The reversal of 216581316 is 613185612.

It is an unprimeable number.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 1289091 + ... + 1289258.

It is an arithmetic number, because the mean of its divisors is an integer number (24064600).

Almost surely, 2^216581316 is an apocalyptic number.

It is an amenable number.

216581316 is an abundant number, since it is smaller than the sum of its proper divisors (360969084).

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

216581316 is a wasteful number, since it uses less digits than its factorization.

216581316 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 2578363 (or 2578361 counting only the distinct ones).

The product of its digits is 8640, while the sum is 33.

The square root of 216581316 is about 14716.7019403126. The cubic root of 216581316 is about 600.5377734111.

The spelling of 216581316 in words is "two hundred sixteen million, five hundred eighty-one thousand, three hundred sixteen".