1221603 has 12 divisors (see below), whose sum is σ = 1731480. Its totient is φ = 765952.

The previous prime is 1221601. The next prime is 1221631. The reversal of 1221603 is 3061221.

It is not a de Polignac number, because 1221603 - 2¹ = 1221601 is a prime.

It is not an unprimeable number, because it can be changed into a prime (1221601) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written in 11 ways as a sum of consecutive naturals, for example, 163 + ... + 1571.

It is an arithmetic number, because the mean of its divisors is an integer number (144290).

2^1221603 is an apocalyptic number.

1221603 is a deficient number, since it is larger than the sum of its proper divisors (509877).

1221603 is a wasteful number, since it uses less digits than its factorization.

1221603 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1446 (or 1429 counting only the distinct ones).

The product of its (nonzero) digits is 72, while the sum is 15.

The square root of 1221603 is about 1105.2615075176. The cubic root of 1221603 is about 106.8997517994.

Adding to 1221603 its reverse (3061221), we get a palindrome (4282824).

The spelling of 1221603 in words is "one million, two hundred twenty-one thousand, six hundred three".