1321243203 has 16 divisors (see below), whose sum is σ = 2054412800. Its totient is φ = 754995528.

The previous prime is 1321243199. The next prime is 1321243237. The reversal of 1321243203 is 3023421231.

It is not a de Polignac number, because 1321243203 - 2² = 1321243199 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 1321243203.

It is not an unprimeable number, because it can be changed into a prime (1321243243) by changing a digit.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 640975 + ... + 643032.

It is an arithmetic number, because the mean of its divisors is an integer number (128400800).

Almost surely, 2^1321243203 is an apocalyptic number.

1321243203 is a deficient number, since it is larger than the sum of its proper divisors (733169597).

1321243203 is an equidigital number, since it uses as much as digits as its factorization.

1321243203 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1284031 (or 1284017 counting only the distinct ones).

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

The square root of 1321243203 is about 36348.9092408562. The cubic root of 1321243203 is about 1097.3055826283.

Adding to 1321243203 its reverse (3023421231), we get a palindrome (4344664434).

The spelling of 1321243203 in words is "one billion, three hundred twenty-one million, two hundred forty-three thousand, two hundred three".