1221003243 has 12 divisors (see below), whose sum is σ = 1789995688. Its totient is φ = 801852480.

The previous prime is 1221003239. The next prime is 1221003253. The reversal of 1221003243 is 3423001221.

It is not a de Polignac number, because 1221003243 - 2² = 1221003239 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (1221003233) by changing a digit.

It is a polite number, since it can be written in 11 ways as a sum of consecutive naturals, for example, 1011838 + ... + 1013043.

Almost surely, 2^1221003243 is an apocalyptic number.

1221003243 is a deficient number, since it is larger than the sum of its proper divisors (568992445).

1221003243 is a wasteful number, since it uses less digits than its factorization.

1221003243 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 2024954 (or 2024951 counting only the distinct ones).

The product of its (nonzero) digits is 288, while the sum is 18.

The square root of 1221003243 is about 34942.8568236771. The cubic root of 1221003243 is about 1068.8225447012.

Adding to 1221003243 its reverse (3423001221), we get a palindrome (4644004464).

The spelling of 1221003243 in words is "one billion, two hundred twenty-one million, three thousand, two hundred forty-three".