1221264064 has 56 divisors (see below), whose sum is σ = 2567645360. Its totient is φ = 574718976.

The previous prime is 1221264061. The next prime is 1221264101. The reversal of 1221264064 is 4604621221.

It is not an unprimeable number, because it can be changed into a prime (1221264061) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 187714 + ... + 194110.

It is an arithmetic number, because the mean of its divisors is an integer number (45850810).

Almost surely, 2^1221264064 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 1221264064, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (1283822680).

1221264064 is an abundant number, since it is smaller than the sum of its proper divisors (1346381296).

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

1221264064 is a wasteful number, since it uses less digits than its factorization.

1221264064 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 6585 (or 6575 counting only the distinct ones).

The product of its (nonzero) digits is 4608, while the sum is 28.

The square root of 1221264064 is about 34946.5887319492. The cubic root of 1221264064 is about 1068.8986437395.

Adding to 1221264064 its reverse (4604621221), we get a palindrome (5825885285).

The spelling of 1221264064 in words is "one billion, two hundred twenty-one million, two hundred sixty-four thousand, sixty-four".