1221011203 has 4 divisors (see below), whose sum is σ = 1234730520. Its totient is φ = 1207291888.

The previous prime is 1221011177. The next prime is 1221011221. The reversal of 1221011203 is 3021101221.

It is a semiprime because it is the product of two primes.

It is a cyclic number.

It is not a de Polignac number, because 1221011203 - 2⁹ = 1221010691 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (1221011243) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 6859525 + ... + 6859702.

It is an arithmetic number, because the mean of its divisors is an integer number (308682630).

Almost surely, 2^1221011203 is an apocalyptic number.

1221011203 is a deficient number, since it is larger than the sum of its proper divisors (13719317).

1221011203 is an equidigital number, since it uses as much as digits as its factorization.

1221011203 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 13719316.

The product of its (nonzero) digits is 24, while the sum is 13.

The square root of 1221011203 is about 34942.9707237378. The cubic root of 1221011203 is about 1068.8248673292.

Adding to 1221011203 its reverse (3021101221), we get a palindrome (4242112424).

The spelling of 1221011203 in words is "one billion, two hundred twenty-one million, eleven thousand, two hundred three".