212191321 has 2 divisors, whose sum is σ = 212191322. Its totient is φ = 212191320.

The previous prime is 212191319. The next prime is 212191327. The reversal of 212191321 is 123191212.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 212110096 + 81225 = 14564^2 + 285^2 .

It is a cyclic number.

It is not a de Polignac number, because 212191321 - 2¹ = 212191319 is a prime.

Together with 212191319, it forms a pair of twin primes.

It is a junction number, because it is equal to n+sod(n) for n = 212191292 and 212191301.

It is not a weakly prime, because it can be changed into another prime (212191327) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 106095660 + 106095661.

It is an arithmetic number, because the mean of its divisors is an integer number (106095661).

Almost surely, 2^212191321 is an apocalyptic number.

It is an amenable number.

212191321 is a deficient number, since it is larger than the sum of its proper divisors (1).

212191321 is an equidigital number, since it uses as much as digits as its factorization.

212191321 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 216, while the sum is 22.

The square root of 212191321 is about 14566.7882870590. The cubic root of 212191321 is about 596.4525122586.

The spelling of 212191321 in words is "two hundred twelve million, one hundred ninety-one thousand, three hundred twenty-one".