1221144320 has 72 divisors (see below), whose sum is σ = 3190970160. Its totient is φ = 444047360.

The previous prime is 1221144319. The next prime is 1221144341. The reversal of 1221144320 is 234411221.

It is a Harshad number since it is a multiple of its sum of digits (20).

It is a junction number, because it is equal to n+sod(n) for n = 1221144292 and 1221144301.

It is a congruent number.

It is an unprimeable number.

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, 29285 + ... + 57444.

It is an arithmetic number, because the mean of its divisors is an integer number (44319030).

Almost surely, 2^1221144320 is an apocalyptic number.

1221144320 is a gapful number since it is divisible by the number (10) formed by its first and last digit.

It is an amenable number.

1221144320 is an abundant number, since it is smaller than the sum of its proper divisors (1969825840).

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

1221144320 is an equidigital number, since it uses as much as digits as its factorization.

1221144320 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 86761 (or 86747 counting only the distinct ones).

The product of its (nonzero) digits is 384, while the sum is 20.

The square root of 1221144320 is about 34944.8754469092. The cubic root of 1221144320 is about 1068.8637077017.

Adding to 1221144320 its reverse (234411221), we get a palindrome (1455555541).

It can be divided in two parts, 1221 and 144320, that added together give a palindrome (145541).

The spelling of 1221144320 in words is "one billion, two hundred twenty-one million, one hundred forty-four thousand, three hundred twenty".