1221128064 has 192 divisors, whose sum is σ = 3843861840. Its totient is φ = 369819648.

The previous prime is 1221128039. The next prime is 1221128093. The reversal of 1221128064 is 4608211221.

It is a tau number, because it is divible by the number of its divisors (192).

It is a congruent number.

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, 1002784 + ... + 1004000.

Almost surely, 2^1221128064 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 1221128064, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (1921930920).

1221128064 is an abundant number, since it is smaller than the sum of its proper divisors (2622733776).

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

1221128064 is a wasteful number, since it uses less digits than its factorization.

1221128064 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1317 (or 1302 counting only the distinct ones).

The product of its (nonzero) digits is 1536, while the sum is 27.

The square root of 1221128064 is about 34944.6428512297. The cubic root of 1221128064 is about 1068.8589647391.

Adding to 1221128064 its reverse (4608211221), we get a palindrome (5829339285).

The spelling of 1221128064 in words is "one billion, two hundred twenty-one million, one hundred twenty-eight thousand, sixty-four".