1221324656 has 20 divisors (see below), whose sum is σ = 2469200592. Its totient is φ = 584111616.

The previous prime is 1221324641. The next prime is 1221324667. The reversal of 1221324656 is 6564231221.

It is a congruent number.

It is an unprimeable number.

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 3 ways as a sum of consecutive naturals, for example, 1659041 + ... + 1659776.

Almost surely, 2^1221324656 is an apocalyptic number.

1221324656 is a gapful number since it is divisible by the number (16) formed by its first and last digit.

It is an amenable number.

1221324656 is an abundant number, since it is smaller than the sum of its proper divisors (1247875936).

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

1221324656 is a wasteful number, since it uses less digits than its factorization.

1221324656 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 3318848 (or 3318842 counting only the distinct ones).

The product of its digits is 17280, while the sum is 32.

The square root of 1221324656 is about 34947.4556441524. The cubic root of 1221324656 is about 1068.9163209527.

Adding to 1221324656 its reverse (6564231221), we get a palindrome (7785555877).

The spelling of 1221324656 in words is "one billion, two hundred twenty-one million, three hundred twenty-four thousand, six hundred fifty-six".