216611213220 has 72 divisors (see below), whose sum is σ = 679711064760. Its totient is φ = 55771161600.

The previous prime is 216611213171. The next prime is 216611213239. The reversal of 216611213220 is 22312116612.

216611213220 is a `hidden beast` number, since 2 + 1 + 6 + 611 + 21 + 3 + 2 + 20 = 666.

216611213220 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.

It can be written as a sum of positive squares in 4 ways, for example, as 90580533156 + 126030680064 = 300966^2 + 355008^2 .

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (19) of ones.

It is a polite number, since it can be written in 23 ways as a sum of consecutive naturals, for example, 20742981 + ... + 20753420.

It is an arithmetic number, because the mean of its divisors is an integer number (9440431455).

Almost surely, 2^216611213220 is an apocalyptic number.

216611213220 is a gapful number since it is divisible by the number (20) formed by its first and last digit.

It is an amenable number.

216611213220 is an abundant number, since it is smaller than the sum of its proper divisors (463099851540).

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

216611213220 is a wasteful number, since it uses less digits than its factorization.

216611213220 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 41496445 (or 41496440 counting only the distinct ones).

The product of its (nonzero) digits is 1728, while the sum is 27.

Adding to 216611213220 its reverse (22312116612), we get a palindrome (238923329832).

The spelling of 216611213220 in words is "two hundred sixteen billion, six hundred eleven million, two hundred thirteen thousand, two hundred twenty".