213116221 has 2 divisors, whose sum is σ = 213116222. Its totient is φ = 213116220.

The previous prime is 213116209. The next prime is 213116243. The reversal of 213116221 is 122611312.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 211702500 + 1413721 = 14550^2 + 1189^2 .

It is a cyclic number.

It is not a de Polignac number, because 213116221 - 2⁷ = 213116093 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (213116251) 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 as a sum of consecutive naturals, namely, 106558110 + 106558111.

It is an arithmetic number, because the mean of its divisors is an integer number (106558111).

Almost surely, 2^213116221 is an apocalyptic number.

It is an amenable number.

213116221 is a deficient number, since it is larger than the sum of its proper divisors (1).

213116221 is an equidigital number, since it uses as much as digits as its factorization.

213116221 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 144, while the sum is 19.

The square root of 213116221 is about 14598.5006421893. The cubic root of 213116221 is about 597.3178623544.

Adding to 213116221 its reverse (122611312), we get a palindrome (335727533).

The spelling of 213116221 in words is "two hundred thirteen million, one hundred sixteen thousand, two hundred twenty-one".