211221331 has 2 divisors, whose sum is σ = 211221332. Its totient is φ = 211221330.

The previous prime is 211221313. The next prime is 211221343. The reversal of 211221331 is 133122112.

Together with previous prime (211221313) it forms an Ormiston pair, because they use the same digits, order apart.

It is a strong prime.

It is a cyclic number.

It is not a de Polignac number, because 211221331 - 2⁹ = 211220819 is a prime.

It is a super-2 number, since 2×211221331² = 89228901338823122, which contains 22 as substring.

It is not a weakly prime, because it can be changed into another prime (211221301) 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, 105610665 + 105610666.

It is an arithmetic number, because the mean of its divisors is an integer number (105610666).

Almost surely, 2^211221331 is an apocalyptic number.

211221331 is a deficient number, since it is larger than the sum of its proper divisors (1).

211221331 is an equidigital number, since it uses as much as digits as its factorization.

211221331 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 72, while the sum is 16.

The square root of 211221331 is about 14533.4555767030. The cubic root of 211221331 is about 595.5422695667.

Adding to 211221331 its reverse (133122112), we get a palindrome (344343443).

The spelling of 211221331 in words is "two hundred eleven million, two hundred twenty-one thousand, three hundred thirty-one".