1221145145 has 16 divisors (see below), whose sum is σ = 1609329600. Its totient is φ = 882139200.

The previous prime is 1221145127. The next prime is 1221145169. The reversal of 1221145145 is 5415411221.

It is a happy number.

It is not a de Polignac number, because 1221145145 - 2¹⁰ = 1221144121 is a prime.

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 15 ways as a sum of consecutive naturals, for example, 66311 + ... + 82700.

It is an arithmetic number, because the mean of its divisors is an integer number (100583100).

Almost surely, 2^1221145145 is an apocalyptic number.

It is an amenable number.

1221145145 is a deficient number, since it is larger than the sum of its proper divisors (388184455).

1221145145 is a wasteful number, since it uses less digits than its factorization.

1221145145 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 149176.

The product of its digits is 1600, while the sum is 26.

The square root of 1221145145 is about 34944.8872512132. The cubic root of 1221145145 is about 1068.8639484082.

Adding to 1221145145 its reverse (5415411221), we get a palindrome (6636556366).

The spelling of 1221145145 in words is "one billion, two hundred twenty-one million, one hundred forty-five thousand, one hundred forty-five".