1980689 has 6 divisors (see below), whose sum is σ = 2018370. Its totient is φ = 1943696.

The previous prime is 1980673. The next prime is 1980697. The reversal of 1980689 is 9860891.

It can be written as a sum of positive squares in only one way, i.e., 1392400 + 588289 = 1180^2 + 767^2 .

It is not a de Polignac number, because 1980689 - 2⁴ = 1980673 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (1980659) by changing a digit.

It is a polite number, since it can be written in 5 ways as a sum of consecutive naturals, for example, 3197 + ... + 3765.

It is an arithmetic number, because the mean of its divisors is an integer number (336395).

2^1980689 is an apocalyptic number.

It is an amenable number.

1980689 is a deficient number, since it is larger than the sum of its proper divisors (37681).

1980689 is an frugal number, since it uses more digits than its factorization.

1980689 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 687 (or 628 counting only the distinct ones).

The product of its (nonzero) digits is 31104, while the sum is 41.

The square root of 1980689 is about 1407.3695321414. The cubic root of 1980689 is about 125.5852872336.

It can be divided in two parts, 19 and 80689, that added together give a palindrome (80708).

The spelling of 1980689 in words is "one million, nine hundred eighty thousand, six hundred eighty-nine".