1221000321 has 4 divisors (see below), whose sum is σ = 1628000432. Its totient is φ = 814000212.

The previous prime is 1221000283. The next prime is 1221000323. The reversal of 1221000321 is 1230001221.

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.

It is not a de Polignac number, because 1221000321 - 2¹⁸ = 1220738177 is a prime.

It is a Duffinian number.

It is a junction number, because it is equal to n+sod(n) for n = 1221000297 and 1221000306.

It is not an unprimeable number, because it can be changed into a prime (1221000323) 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, 203500051 + ... + 203500056.

It is an arithmetic number, because the mean of its divisors is an integer number (407000108).

Almost surely, 2^1221000321 is an apocalyptic number.

It is an amenable number.

1221000321 is a deficient number, since it is larger than the sum of its proper divisors (407000111).

1221000321 is an equidigital number, since it uses as much as digits as its factorization.

1221000321 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 407000110.

The product of its (nonzero) digits is 24, while the sum is 12.

The square root of 1221000321 is about 34942.8150125315. The cubic root of 1221000321 is about 1068.8216920958.

Adding to 1221000321 its reverse (1230001221), we get a palindrome (2451001542).

The spelling of 1221000321 in words is "one billion, two hundred twenty-one million, three hundred twenty-one", and thus it is an aban number.