1320721920 has 480 divisors, whose sum is σ = 5515361280. Its totient is φ = 285327360.

The previous prime is 1320721867. The next prime is 1320721931. The reversal of 1320721920 is 291270231.

It is a tau number, because it is divible by the number of its divisors (480).

It is a congruent number.

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 47 ways as a sum of consecutive naturals, for example, 3064105 + ... + 3064535.

It is an arithmetic number, because the mean of its divisors is an integer number (11490336).

Almost surely, 2^1320721920 is an apocalyptic number.

1320721920 is a gapful number since it is divisible by the number (10) formed by its first and last digit.

It is an amenable number.

It is a practical number, because each smaller number is the sum of distinct divisors of 1320721920, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (2757680640).

1320721920 is an abundant number, since it is smaller than the sum of its proper divisors (4194639360).

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

1320721920 is a wasteful number, since it uses less digits than its factorization.

1320721920 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 486 (or 467 counting only the distinct ones).

The product of its (nonzero) digits is 1512, while the sum is 27.

The square root of 1320721920 is about 36341.7379881590. The cubic root of 1320721920 is about 1097.1612534118.

The spelling of 1320721920 in words is "one billion, three hundred twenty million, seven hundred twenty-one thousand, nine hundred twenty".