216665560 has 16 divisors (see below), whose sum is σ = 487497600. Its totient is φ = 86666208.

The previous prime is 216665551. The next prime is 216665563. The reversal of 216665560 is 65566612.

216665560 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.

It is a super-2 number, since 2×216665560² = 93887929780227200, which contains 22 as substring.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (216665563) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 2708280 + ... + 2708359.

It is an arithmetic number, because the mean of its divisors is an integer number (30468600).

Almost surely, 2^216665560 is an apocalyptic number.

216665560 is a gapful number since it is divisible by the number (20) formed by its first and last digit.

It is an amenable number.

216665560 is an abundant number, since it is smaller than the sum of its proper divisors (270832040).

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

216665560 is a wasteful number, since it uses less digits than its factorization.

216665560 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 5416650 (or 5416646 counting only the distinct ones).

The product of its (nonzero) digits is 64800, while the sum is 37.

The square root of 216665560 is about 14719.5638522342. The cubic root of 216665560 is about 600.6156273814.

The spelling of 216665560 in words is "two hundred sixteen million, six hundred sixty-five thousand, five hundred sixty".