1221303121 has 4 divisors (see below), whose sum is σ = 1251091044. Its totient is φ = 1191515200.

The previous prime is 1221303119. The next prime is 1221303133. The reversal of 1221303121 is 1213031221.

It is a semiprime because it is the product of two primes.

It can be written as a sum of positive squares in 2 ways, for example, as 107412496 + 1113890625 = 10364^2 + 33375^2 .

It is a cyclic number.

It is not a de Polignac number, because 1221303121 - 2¹ = 1221303119 is a prime.

It is a Duffinian number.

It is a junction number, because it is equal to n+sod(n) for n = 1221303095 and 1221303104.

It is not an unprimeable number, because it can be changed into a prime (1221303101) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 14893900 + ... + 14893981.

It is an arithmetic number, because the mean of its divisors is an integer number (312772761).

Almost surely, 2^1221303121 is an apocalyptic number.

It is an amenable number.

1221303121 is a deficient number, since it is larger than the sum of its proper divisors (29787923).

1221303121 is an equidigital number, since it uses as much as digits as its factorization.

1221303121 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 29787922.

The product of its (nonzero) digits is 72, while the sum is 16.

The square root of 1221303121 is about 34947.1475373885. The cubic root of 1221303121 is about 1068.9100383621.

Adding to 1221303121 its reverse (1213031221), we get a palindrome (2434334342).

It can be divided in two parts, 1 and 221303121, that added together give a palindrome (221303122).

The spelling of 1221303121 in words is "one billion, two hundred twenty-one million, three hundred three thousand, one hundred twenty-one".