1221517264 has 80 divisors (see below), whose sum is σ = 2668579200. Its totient is φ = 541305600.

The previous prime is 1221517261. The next prime is 1221517279. The reversal of 1221517264 is 4627151221.

It is a hoax number, since the sum of its digits (31) coincides with the sum of the digits of its distinct prime factors.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (1221517261) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 872437 + ... + 873835.

It is an arithmetic number, because the mean of its divisors is an integer number (33357240).

Almost surely, 2^1221517264 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 1221517264, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (1334289600).

1221517264 is an abundant number, since it is smaller than the sum of its proper divisors (1447061936).

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

1221517264 is a wasteful number, since it uses less digits than its factorization.

1221517264 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1481 (or 1453 counting only the distinct ones).

The product of its digits is 6720, while the sum is 31.

The square root of 1221517264 is about 34950.2112153847. The cubic root of 1221517264 is about 1068.9725088554.

Adding to 1221517264 its reverse (4627151221), we get a palindrome (5848668485).

The spelling of 1221517264 in words is "one billion, two hundred twenty-one million, five hundred seventeen thousand, two hundred sixty-four".