1981320 has 128 divisors (see below), whose sum is σ = 6912000. Its totient is φ = 449280.

The previous prime is 1981297. The next prime is 1981337. The reversal of 1981320 is 231891.

It is a super-3 number, since 3×1981320³ = 23333781408467904000, which contains 333 as substring.

It is a Harshad number since it is a multiple of its sum of digits (24).

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 31 ways as a sum of consecutive naturals, for example, 25041 + ... + 25119.

It is an arithmetic number, because the mean of its divisors is an integer number (54000).

2^1981320 is an apocalyptic number.

1981320 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 1981320, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (3456000).

1981320 is an abundant number, since it is smaller than the sum of its proper divisors (4930680).

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

1981320 is a wasteful number, since it uses less digits than its factorization.

1981320 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 123 (or 119 counting only the distinct ones).

The product of its (nonzero) digits is 432, while the sum is 24.

The square root of 1981320 is about 1407.5936913755. The cubic root of 1981320 is about 125.5986219709.

The spelling of 1981320 in words is "one million, nine hundred eighty-one thousand, three hundred twenty".