1981328 has 10 divisors (see below), whose sum is σ = 3838854. Its totient is φ = 990656.

The previous prime is 1981297. The next prime is 1981337. The reversal of 1981328 is 8231891.

It can be written as a sum of positive squares in only one way, i.e., 1507984 + 473344 = 1228^2 + 688^2 .

It is a super-3 number, since 3×1981328³ = 23334064054892998656, which contains 333 as substring.

It is an Ulam number.

It is a plaindrome in base 11.

It is a junction number, because it is equal to n+sod(n) for n = 1981294 and 1981303.

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 as a sum of consecutive naturals, namely, 61901 + ... + 61932.

2^1981328 is an apocalyptic number.

It is an amenable number.

1981328 is a deficient number, since it is larger than the sum of its proper divisors (1857526).

1981328 is a wasteful number, since it uses less digits than its factorization.

1981328 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 123841 (or 123835 counting only the distinct ones).

The product of its digits is 3456, while the sum is 32.

The square root of 1981328 is about 1407.5965331017. The cubic root of 1981328 is about 125.5987910144.

The spelling of 1981328 in words is "one million, nine hundred eighty-one thousand, three hundred twenty-eight".