1221653568 has 112 divisors (see below), whose sum is σ = 3335731200. Its totient is φ = 394297344.

The previous prime is 1221653567. The next prime is 1221653591. The reversal of 1221653568 is 8653561221.

It is not an unprimeable number, because it can be changed into a prime (1221653567) by changing a digit.

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 15 ways as a sum of consecutive naturals, for example, 2720608 + ... + 2721056.

Almost surely, 2^1221653568 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 1221653568, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (1667865600).

1221653568 is an abundant number, since it is smaller than the sum of its proper divisors (2114077632).

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

1221653568 is a wasteful number, since it uses less digits than its factorization.

1221653568 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 884 (or 874 counting only the distinct ones).

The product of its digits is 86400, while the sum is 39.

The square root of 1221653568 is about 34952.1611348998. The cubic root of 1221653568 is about 1069.0122680996.

It can be divided in two parts, 1221653 and 568, that added together give a palindrome (1222221).

The spelling of 1221653568 in words is "one billion, two hundred twenty-one million, six hundred fifty-three thousand, five hundred sixty-eight".