1221248320 has 56 divisors (see below), whose sum is σ = 2911915944. Its totient is φ = 487858176.

The previous prime is 1221248279. The next prime is 1221248321. The reversal of 1221248320 is 238421221.

It can be written as a sum of positive squares in 4 ways, for example, as 39538944 + 1181709376 = 6288^2 + 34376^2 .

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (1221248321) 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 7 ways as a sum of consecutive naturals, for example, 297804 + ... + 301876.

It is an arithmetic number, because the mean of its divisors is an integer number (51998499).

Almost surely, 2^1221248320 is an apocalyptic number.

1221248320 is a gapful number since it is divisible by the number (10) formed by its first and last digit.

It is an amenable number.

1221248320 is an abundant number, since it is smaller than the sum of its proper divisors (1690667624).

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

1221248320 is an equidigital number, since it uses as much as digits as its factorization.

1221248320 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 5027 (or 5017 counting only the distinct ones).

The product of its (nonzero) digits is 1536, while the sum is 25.

The square root of 1221248320 is about 34946.3634731856. The cubic root of 1221248320 is about 1068.8940504625.

Adding to 1221248320 its reverse (238421221), we get a palindrome (1459669541).

The spelling of 1221248320 in words is "one billion, two hundred twenty-one million, two hundred forty-eight thousand, three hundred twenty".