1221312123 has 12 divisors (see below), whose sum is σ = 1764499360. Its totient is φ = 814031856.

The previous prime is 1221312091. The next prime is 1221312149. The reversal of 1221312123 is 3212131221.

It is not a de Polignac number, because 1221312123 - 2⁵ = 1221312091 is a prime.

It is a Duffinian number.

It is a junction number, because it is equal to n+sod(n) for n = 1221312096 and 1221312105.

It is not an unprimeable number, because it can be changed into a prime (1221312173) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (19) of ones.

It is a polite number, since it can be written in 11 ways as a sum of consecutive naturals, for example, 39873 + ... + 63501.

Almost surely, 2^1221312123 is an apocalyptic number.

1221312123 is a deficient number, since it is larger than the sum of its proper divisors (543187237).

1221312123 is a wasteful number, since it uses less digits than its factorization.

1221312123 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 29378 (or 29375 counting only the distinct ones).

The product of its digits is 144, while the sum is 18.

The square root of 1221312123 is about 34947.2763316399. The cubic root of 1221312123 is about 1068.9126646019.

Adding to 1221312123 its reverse (3212131221), we get a palindrome (4433443344).

It can be divided in two parts, 12213 and 12123, that added together give a square (24336 = 156²).

The spelling of 1221312123 in words is "one billion, two hundred twenty-one million, three hundred twelve thousand, one hundred twenty-three".