1221243303 has 32 divisors (see below), whose sum is σ = 1893253120. Its totient is φ = 685843200.

The previous prime is 1221243281. The next prime is 1221243307. The reversal of 1221243303 is 3033421221.

It is not a de Polignac number, because 1221243303 - 2¹⁶ = 1221177767 is a prime.

It is a Harshad number since it is a multiple of its sum of digits (21).

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 1221243303.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (1221243307) by changing a digit.

It is a polite number, since it can be written in 31 ways as a sum of consecutive naturals, for example, 288603 + ... + 292803.

It is an arithmetic number, because the mean of its divisors is an integer number (59164160).

Almost surely, 2^1221243303 is an apocalyptic number.

1221243303 is a deficient number, since it is larger than the sum of its proper divisors (672009817).

1221243303 is a wasteful number, since it uses less digits than its factorization.

1221243303 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 4447.

The product of its (nonzero) digits is 864, while the sum is 21.

The square root of 1221243303 is about 34946.2916916802. The cubic root of 1221243303 is about 1068.8925867556.

Adding to 1221243303 its reverse (3033421221), we get a palindrome (4254664524).

The spelling of 1221243303 in words is "one billion, two hundred twenty-one million, two hundred forty-three thousand, three hundred three".