1221321003 has 16 divisors (see below), whose sum is σ = 1870513920. Its totient is φ = 694352736.

The previous prime is 1221321001. The next prime is 1221321011. The reversal of 1221321003 is 3001231221.

It is not a de Polignac number, because 1221321003 - 2¹ = 1221321001 is a prime.

It is not an unprimeable number, because it can be changed into a prime (1221321001) 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, 143473 + ... + 151746.

It is an arithmetic number, because the mean of its divisors is an integer number (116907120).

Almost surely, 2^1221321003 is an apocalyptic number.

1221321003 is a deficient number, since it is larger than the sum of its proper divisors (649192917).

1221321003 is a wasteful number, since it uses less digits than its factorization.

1221321003 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 295426.

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

The square root of 1221321003 is about 34947.4033799365. The cubic root of 1221321003 is about 1068.9152552368.

Adding to 1221321003 its reverse (3001231221), we get a palindrome (4222552224).

It can be divided in two parts, 122 and 1321003, that added together give a triangular number (1321125 = T₁₆₂₅).

The spelling of 1221321003 in words is "one billion, two hundred twenty-one million, three hundred twenty-one thousand, three".