1221313503 has 16 divisors (see below), whose sum is σ = 1661212800. Its totient is φ = 797850144.

The previous prime is 1221313493. The next prime is 1221313553. The reversal of 1221313503 is 3053131221.

It is not a de Polignac number, because 1221313503 - 2⁴ = 1221313487 is a prime.

It is a super-2 number, since 2×1221313503² = 2983213345220262018, which contains 22 as substring.

It is a self number, because there is not a number n which added to its sum of digits gives 1221313503.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (1221313553) by changing a digit.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 136048 + ... + 144746.

It is an arithmetic number, because the mean of its divisors is an integer number (103825800).

Almost surely, 2^1221313503 is an apocalyptic number.

1221313503 is a deficient number, since it is larger than the sum of its proper divisors (439899297).

1221313503 is an equidigital number, since it uses as much as digits as its factorization.

1221313503 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 9638.

The product of its (nonzero) digits is 540, while the sum is 21.

The square root of 1221313503 is about 34947.2960756623. The cubic root of 1221313503 is about 1068.9130672014.

Adding to 1221313503 its reverse (3053131221), we get a palindrome (4274444724).

The spelling of 1221313503 in words is "one billion, two hundred twenty-one million, three hundred thirteen thousand, five hundred three".