1221003 has 12 divisors (see below), whose sum is σ = 2015728. Its totient is φ = 697680.

The previous prime is 1220993. The next prime is 1221019. The reversal of 1221003 is 3001221.

It is a happy number.

It is not a de Polignac number, because 1221003 - 2⁹ = 1220491 is a prime.

It is a Harshad number since it is a multiple of its sum of digits (9).

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (1221083) 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, 9628 + ... + 9753.

2^1221003 is an apocalyptic number.

1221003 is a deficient number, since it is larger than the sum of its proper divisors (794725).

1221003 is a wasteful number, since it uses less digits than its factorization.

1221003 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 19394 (or 19391 counting only the distinct ones).

The product of its (nonzero) digits is 12, while the sum is 9.

The square root of 1221003 is about 1104.9900452040. The cubic root of 1221003 is about 106.8822473797.

Adding to 1221003 its reverse (3001221), we get a palindrome (4222224).

The spelling of 1221003 in words is "one million, two hundred twenty-one thousand, three".