1221403 has 4 divisors (see below), whose sum is σ = 1241488. Its totient is φ = 1201320.

The previous prime is 1221391. The next prime is 1221421. The reversal of 1221403 is 3041221.

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

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-1221403 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (1221443) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 9951 + ... + 10072.

It is an arithmetic number, because the mean of its divisors is an integer number (310372).

2^1221403 is an apocalyptic number.

1221403 is a deficient number, since it is larger than the sum of its proper divisors (20085).

1221403 is an equidigital number, since it uses as much as digits as its factorization.

1221403 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 20084.

The product of its (nonzero) digits is 48, while the sum is 13.

The square root of 1221403 is about 1105.1710274885. The cubic root of 1221403 is about 106.8939176298.

Adding to 1221403 its reverse (3041221), we get a palindrome (4262624).

The spelling of 1221403 in words is "one million, two hundred twenty-one thousand, four hundred three".