216126221 has 2 divisors, whose sum is σ = 216126222. Its totient is φ = 216126220.

The previous prime is 216126191. The next prime is 216126227. The reversal of 216126221 is 122621612.

It is a happy number.

216126221 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 128029225 + 88096996 = 11315^2 + 9386^2 .

It is a cyclic number.

It is not a de Polignac number, because 216126221 - 2²⁶ = 149017357 is a prime.

It is a Chen prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (216126227) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 108063110 + 108063111.

It is an arithmetic number, because the mean of its divisors is an integer number (108063111).

Almost surely, 2^216126221 is an apocalyptic number.

It is an amenable number.

216126221 is a deficient number, since it is larger than the sum of its proper divisors (1).

216126221 is an equidigital number, since it uses as much as digits as its factorization.

216126221 is an evil number, because the sum of its binary digits is even.

The product of its digits is 576, while the sum is 23.

The square root of 216126221 is about 14701.2319551798. The cubic root of 216126221 is about 600.1168485389.

Adding to 216126221 its reverse (122621612), we get a palindrome (338747833).

It can be divided in two parts, 2161 and 26221, that added together give a palindrome (28382).

The spelling of 216126221 in words is "two hundred sixteen million, one hundred twenty-six thousand, two hundred twenty-one".