1982009 has 4 divisors (see below), whose sum is σ = 1986804. Its totient is φ = 1977216.

The previous prime is 1981997. The next prime is 1982011. The reversal of 1982009 is 9002891.

It is a semiprime because it is the product of two primes.

It can be written as a sum of positive squares in 2 ways, for example, as 727609 + 1254400 = 853^2 + 1120^2 .

It is a cyclic number.

It is not a de Polignac number, because 1982009 - 2⁸ = 1981753 is a prime.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (1982059) by changing a digit.

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 3 ways as a sum of consecutive naturals, for example, 1712 + ... + 2625.

It is an arithmetic number, because the mean of its divisors is an integer number (496701).

2^1982009 is an apocalyptic number.

It is an amenable number.

1982009 is a deficient number, since it is larger than the sum of its proper divisors (4795).

1982009 is an equidigital number, since it uses as much as digits as its factorization.

1982009 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 4794.

The product of its (nonzero) digits is 1296, while the sum is 29.

The square root of 1982009 is about 1407.8384140234. The cubic root of 1982009 is about 125.6131791721.

It can be divided in two parts, 19 and 82009, that added together give a palindrome (82028).

The spelling of 1982009 in words is "one million, nine hundred eighty-two thousand, nine".