105212321 has 2 divisors, whose sum is σ = 105212322. Its totient is φ = 105212320.

The previous prime is 105212299. The next prime is 105212323. The reversal of 105212321 is 123212501.

It is a happy number.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 79405921 + 25806400 = 8911^2 + 5080^2 .

It is a cyclic number.

It is not a de Polignac number, because 105212321 - 2¹⁸ = 104950177 is a prime.

It is a super-2 number, since 2×105212321² = 22139264980414082, which contains 22 as substring.

Together with 105212323, it forms a pair of twin primes.

It is a Chen prime.

It is an alternating number because its digits alternate between odd and even.

It is a self number, because there is not a number n which added to its sum of digits gives 105212321.

It is not a weakly prime, because it can be changed into another prime (105212323) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 52606160 + 52606161.

It is an arithmetic number, because the mean of its divisors is an integer number (52606161).

Almost surely, 2^105212321 is an apocalyptic number.

It is an amenable number.

105212321 is a deficient number, since it is larger than the sum of its proper divisors (1).

105212321 is an equidigital number, since it uses as much as digits as its factorization.

105212321 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 120, while the sum is 17.

The square root of 105212321 is about 10257.3057378631. The cubic root of 105212321 is about 472.0871729851.

Adding to 105212321 its reverse (123212501), we get a palindrome (228424822).

The spelling of 105212321 in words is "one hundred five million, two hundred twelve thousand, three hundred twenty-one".