1221144145 has 24 divisors (see below), whose sum is σ = 1590092856. Its totient is φ = 899877888.

The previous prime is 1221144139. The next prime is 1221144161. The reversal of 1221144145 is 5414411221.

It can be written as a sum of positive squares in 12 ways, for example, as 307230784 + 913913361 = 17528^2 + 30231^2 .

It is not a de Polignac number, because 1221144145 - 2⁹ = 1221143633 is a prime.

It is a Duffinian number.

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 23 ways as a sum of consecutive naturals, for example, 499867 + ... + 502303.

It is an arithmetic number, because the mean of its divisors is an integer number (66253869).

Almost surely, 2^1221144145 is an apocalyptic number.

It is an amenable number.

1221144145 is a deficient number, since it is larger than the sum of its proper divisors (368948711).

1221144145 is a wasteful number, since it uses less digits than its factorization.

1221144145 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 3061 (or 3048 counting only the distinct ones).

The product of its digits is 1280, while the sum is 25.

The square root of 1221144145 is about 34944.8729429655. The cubic root of 1221144145 is about 1068.8636566427.

Adding to 1221144145 its reverse (5414411221), we get a palindrome (6635555366).

The spelling of 1221144145 in words is "one billion, two hundred twenty-one million, one hundred forty-four thousand, one hundred forty-five".