1221144515 has 4 divisors (see below), whose sum is σ = 1465373424. Its totient is φ = 976915608.

The previous prime is 1221144503. The next prime is 1221144523. The reversal of 1221144515 is 5154411221.

It is a happy number.

It is a semiprime because it is the product of two primes, and also an emirpimes, since its reverse is a distinct semiprime: 5154411221 = 1321 ⋅3901901.

It is a cyclic number.

It is not a de Polignac number, because 1221144515 - 2⁸ = 1221144259 is a prime.

It is a Duffinian number.

It is an unprimeable number.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 122114447 + ... + 122114456.

It is an arithmetic number, because the mean of its divisors is an integer number (366343356).

Almost surely, 2^1221144515 is an apocalyptic number.

1221144515 is a deficient number, since it is larger than the sum of its proper divisors (244228909).

1221144515 is an equidigital number, since it uses as much as digits as its factorization.

1221144515 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 244228908.

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

The square root of 1221144515 is about 34944.8782370178. The cubic root of 1221144515 is about 1068.8637645960.

Adding to 1221144515 its reverse (5154411221), we get a palindrome (6375555736).

The spelling of 1221144515 in words is "one billion, two hundred twenty-one million, one hundred forty-four thousand, five hundred fifteen".