1221321123 has 72 divisors (see below), whose sum is σ = 2109822624. Its totient is φ = 677445120.

The previous prime is 1221321113. The next prime is 1221321133. The reversal of 1221321123 is 3211231221.

1221321123 is a `hidden beast` number, since 1 + 221 + 321 + 123 = 666.

It is an interprime number because it is at equal distance from previous prime (1221321113) and next prime (1221321133).

It is not a de Polignac number, because 1221321123 - 2²⁵ = 1187766691 is a prime.

It is a super-2 number, since 2×1221321123² = 2983250570971962258, which contains 22 as substring.

It is a junction number, because it is equal to n+sod(n) for n = 1221321096 and 1221321105.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (1221321103) by changing a digit.

It is a polite number, since it can be written in 71 ways as a sum of consecutive naturals, for example, 684090 + ... + 685872.

It is an arithmetic number, because the mean of its divisors is an integer number (29303092).

Almost surely, 2^1221321123 is an apocalyptic number.

1221321123 is a deficient number, since it is larger than the sum of its proper divisors (888501501).

1221321123 is a wasteful number, since it uses less digits than its factorization.

1221321123 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1865 (or 1851 counting only the distinct ones).

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

The square root of 1221321123 is about 34947.4050968023. The cubic root of 1221321123 is about 1068.9152902453.

Adding to 1221321123 its reverse (3211231221), we get a palindrome (4432552344).

The spelling of 1221321123 in words is "one billion, two hundred twenty-one million, three hundred twenty-one thousand, one hundred twenty-three".