331220321 has 4 divisors (see below), whose sum is σ = 331302144. Its totient is φ = 331138500.

The previous prime is 331220311. The next prime is 331220341. The reversal of 331220321 is 123022133.

It is a semiprime because it is the product of two primes, and also a Blum integer, because the two primes are equal to 3 mod 4, and also an emirpimes, since its reverse is a distinct semiprime: 123022133 = 13 ⋅9463241.

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-331220321 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 331220321.

It is not an unprimeable number, because it can be changed into a prime (331220311) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 34505 + ... + 43046.

It is an arithmetic number, because the mean of its divisors is an integer number (82825536).

Almost surely, 2^331220321 is an apocalyptic number.

It is an amenable number.

331220321 is a deficient number, since it is larger than the sum of its proper divisors (81823).

331220321 is an equidigital number, since it uses as much as digits as its factorization.

331220321 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 81822.

The product of its (nonzero) digits is 216, while the sum is 17.

The square root of 331220321 is about 18199.4593601019. The cubic root of 331220321 is about 691.8930867439.

Adding to 331220321 its reverse (123022133), we get a palindrome (454242454).

The spelling of 331220321 in words is "three hundred thirty-one million, two hundred twenty thousand, three hundred twenty-one".