216352210221 has 60 divisors (see below), whose sum is σ = 386120296188. Its totient is φ = 120288405888.

The previous prime is 216352210157. The next prime is 216352210223. The reversal of 216352210221 is 122012253612.

216352210221 is a `hidden beast` number, since 2 + 1 + 635 + 2 + 2 + 1 + 0 + 2 + 21 = 666.

It can be written as a sum of positive squares in 2 ways, for example, as 188416764900 + 27935445321 = 434070^2 + 167139^2 .

It is not a de Polignac number, because 216352210221 - 2⁶ = 216352210157 is a prime.

It is a Harshad number since it is a multiple of its sum of digits (27).

It is a Curzon number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (216352210223) by changing a digit.

It is a polite number, since it can be written in 59 ways as a sum of consecutive naturals, for example, 589776 + ... + 883481.

Almost surely, 2^216352210221 is an apocalyptic number.

216352210221 is a gapful number since it is divisible by the number (21) formed by its first and last digit.

It is an amenable number.

216352210221 is a deficient number, since it is larger than the sum of its proper divisors (169768085967).

216352210221 is a wasteful number, since it uses less digits than its factorization.

216352210221 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1473320 (or 1473304 counting only the distinct ones).

The product of its (nonzero) digits is 2880, while the sum is 27.

Adding to 216352210221 its reverse (122012253612), we get a palindrome (338364463833).

The spelling of 216352210221 in words is "two hundred sixteen billion, three hundred fifty-two million, two hundred ten thousand, two hundred twenty-one".