1221105512 has 96 divisors (see below), whose sum is σ = 2766415680. Its totient is φ = 499361280.

The previous prime is 1221105493. The next prime is 1221105539. The reversal of 1221105512 is 2155011221.

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, 790613 + ... + 792155.

It is an arithmetic number, because the mean of its divisors is an integer number (28816830).

Almost surely, 2^1221105512 is an apocalyptic number.

It is an amenable number.

It is a practical number, because each smaller number is the sum of distinct divisors of 1221105512, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (1383207840).

1221105512 is an abundant number, since it is smaller than the sum of its proper divisors (1545310168).

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

1221105512 is a wasteful number, since it uses less digits than its factorization.

1221105512 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1623 (or 1596 counting only the distinct ones).

The product of its (nonzero) digits is 200, while the sum is 20.

The square root of 1221105512 is about 34944.3201679472. The cubic root of 1221105512 is about 1068.8523847424.

Adding to 1221105512 its reverse (2155011221), we get a palindrome (3376116733).

The spelling of 1221105512 in words is "one billion, two hundred twenty-one million, one hundred five thousand, five hundred twelve".