212321321 has 4 divisors (see below), whose sum is σ = 213147732. Its totient is φ = 211494912.

The previous prime is 212321309. The next prime is 212321323. The reversal of 212321321 is 123123212.

It is a semiprime because it is the product of two primes.

It can be written as a sum of positive squares in 2 ways, for example, as 147744025 + 64577296 = 12155^2 + 8036^2 .

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-212321321 is a prime.

It is a Duffinian number.

It is a self number, because there is not a number n which added to its sum of digits gives 212321321.

It is not an unprimeable number, because it can be changed into a prime (212321323) 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 in 3 ways as a sum of consecutive naturals, for example, 412820 + ... + 413333.

It is an arithmetic number, because the mean of its divisors is an integer number (53286933).

Almost surely, 2^212321321 is an apocalyptic number.

It is an amenable number.

212321321 is a deficient number, since it is larger than the sum of its proper divisors (826411).

212321321 is an equidigital number, since it uses as much as digits as its factorization.

212321321 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 826410.

The product of its digits is 144, while the sum is 17.

The square root of 212321321 is about 14571.2498091276. The cubic root of 212321321 is about 596.5742938608.

Adding to 212321321 its reverse (123123212), we get a palindrome (335444533).

The spelling of 212321321 in words is "two hundred twelve million, three hundred twenty-one thousand, three hundred twenty-one".