2161214221 has 2 divisors, whose sum is σ = 2161214222. Its totient is φ = 2161214220.

The previous prime is 2161214219. The next prime is 2161214239. The reversal of 2161214221 is 1224121612.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 1780418025 + 380796196 = 42195^2 + 19514^2 .

It is a cyclic number.

It is not a de Polignac number, because 2161214221 - 2¹ = 2161214219 is a prime.

Together with 2161214219, it forms a pair of twin primes.

It is a junction number, because it is equal to n+sod(n) for n = 2161214192 and 2161214201.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (2161214291) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 1080607110 + 1080607111.

It is an arithmetic number, because the mean of its divisors is an integer number (1080607111).

Almost surely, 2^2161214221 is an apocalyptic number.

It is an amenable number.

2161214221 is a deficient number, since it is larger than the sum of its proper divisors (1).

2161214221 is an equidigital number, since it uses as much as digits as its factorization.

2161214221 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 384, while the sum is 22.

The square root of 2161214221 is about 46488.8612572947. The cubic root of 2161214221 is about 1292.9029871505.

Adding to 2161214221 its reverse (1224121612), we get a palindrome (3385335833).

The spelling of 2161214221 in words is "two billion, one hundred sixty-one million, two hundred fourteen thousand, two hundred twenty-one".