216509660 has 24 divisors (see below), whose sum is σ = 459176256. Its totient is φ = 85745600.

The previous prime is 216509659. The next prime is 216509663. The reversal of 216509660 is 66905612.

It is a happy number.

216509660 is digitally balanced in base 3, because in such base it contains all the possibile digits an equal number of times.

It is a self number, because there is not a number n which added to its sum of digits gives 216509660.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (216509663) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 51572 + ... + 55611.

It is an arithmetic number, because the mean of its divisors is an integer number (19132344).

Almost surely, 2^216509660 is an apocalyptic number.

216509660 is a gapful number since it is divisible by the number (20) formed by its first and last digit.

It is an amenable number.

216509660 is an abundant number, since it is smaller than the sum of its proper divisors (242666596).

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

216509660 is a wasteful number, since it uses less digits than its factorization.

216509660 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 107293 (or 107291 counting only the distinct ones).

The product of its (nonzero) digits is 19440, while the sum is 35.

The square root of 216509660 is about 14714.2672260633. The cubic root of 216509660 is about 600.4715367322.

The spelling of 216509660 in words is "two hundred sixteen million, five hundred nine thousand, six hundred sixty".