1221611144 has 32 divisors (see below), whose sum is σ = 2573968320. Its totient is φ = 539305536.

The previous prime is 1221611119. The next prime is 1221611219. The reversal of 1221611144 is 4411161221.

It is a Harshad number since it is a multiple of its sum of digits (23).

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 252962 + ... + 257745.

It is an arithmetic number, because the mean of its divisors is an integer number (80436510).

Almost surely, 2^1221611144 is an apocalyptic number.

It is an amenable number.

1221611144 is an abundant number, since it is smaller than the sum of its proper divisors (1352357176).

It is a pseudoperfect number, because it is the sum of a subset of its proper divisors.

1221611144 is a wasteful number, since it uses less digits than its factorization.

1221611144 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 510749 (or 510745 counting only the distinct ones).

The product of its digits is 384, while the sum is 23.

The square root of 1221611144 is about 34951.5542429804. The cubic root of 1221611144 is about 1068.9998935327. Note that the first 3 decimals are identical.

Adding to 1221611144 its reverse (4411161221), we get a palindrome (5632772365).

The spelling of 1221611144 in words is "one billion, two hundred twenty-one million, six hundred eleven thousand, one hundred forty-four".