216665860 has 12 divisors (see below), whose sum is σ = 454998348. Its totient is φ = 86666336.

The previous prime is 216665849. The next prime is 216665881. The reversal of 216665860 is 68566612.

It can be written as a sum of positive squares in 2 ways, for example, as 69189124 + 147476736 = 8318^2 + 12144^2 .

It is an unprimeable number.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 5416627 + ... + 5416666.

It is an arithmetic number, because the mean of its divisors is an integer number (37916529).

Almost surely, 2^216665860 is an apocalyptic number.

216665860 is a gapful number since it is divisible by the number (20) formed by its first and last digit.

It is an amenable number.

216665860 is an abundant number, since it is smaller than the sum of its proper divisors (238332488).

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

216665860 is a wasteful number, since it uses less digits than its factorization.

216665860 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 10833302 (or 10833300 counting only the distinct ones).

The product of its (nonzero) digits is 103680, while the sum is 40.

The square root of 216665860 is about 14719.5740427500. The cubic root of 216665860 is about 600.6159045899.

The spelling of 216665860 in words is "two hundred sixteen million, six hundred sixty-five thousand, eight hundred sixty".