43220321 has 2 divisors, whose sum is σ = 43220322. Its totient is φ = 43220320.

The previous prime is 43220311. The next prime is 43220323. The reversal of 43220321 is 12302234.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 37149025 + 6071296 = 6095^2 + 2464^2 .

It is a cyclic number.

It is not a de Polignac number, because 43220321 - 2¹⁸ = 42958177 is a prime.

It is a super-2 number, since 2×43220321² = 3735992294686082, which contains 22 as substring.

It is a Sophie Germain prime.

Together with 43220323, it forms a pair of twin primes.

It is a Chen prime.

It is a Curzon number.

It is a self number, because there is not a number n which added to its sum of digits gives 43220321.

It is not a weakly prime, because it can be changed into another prime (43220323) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 21610160 + 21610161.

It is an arithmetic number, because the mean of its divisors is an integer number (21610161).

Almost surely, 2^43220321 is an apocalyptic number.

It is an amenable number.

43220321 is a deficient number, since it is larger than the sum of its proper divisors (1).

43220321 is an equidigital number, since it uses as much as digits as its factorization.

43220321 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 288, while the sum is 17.

The square root of 43220321 is about 6574.2163791588. The cubic root of 43220321 is about 350.9371375208.

Adding to 43220321 its reverse (12302234), we get a palindrome (55522555).

The spelling of 43220321 in words is "forty-three million, two hundred twenty thousand, three hundred twenty-one".