1989765 has 40 divisors (see below), whose sum is σ = 3789720. Its totient is φ = 998784.

The previous prime is 1989721. The next prime is 1989769. The reversal of 1989765 is 5679891.

It can be written as a sum of positive squares in 4 ways, for example, as 263169 + 1726596 = 513^2 + 1314^2 .

It is not a de Polignac number, because 1989765 - 2¹⁴ = 1973381 is a prime.

It is a Harshad number since it is a multiple of its sum of digits (45).

It is a self number, because there is not a number n which added to its sum of digits gives 1989765.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (1989769) by changing a digit.

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 39 ways as a sum of consecutive naturals, for example, 117037 + ... + 117053.

It is an arithmetic number, because the mean of its divisors is an integer number (94743).

2^1989765 is an apocalyptic number.

1989765 is a gapful number since it is divisible by the number (15) formed by its first and last digit.

It is an amenable number.

1989765 is a deficient number, since it is larger than the sum of its proper divisors (1799955).

1989765 is an frugal number, since it uses more digits than its factorization.

1989765 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 68 (or 25 counting only the distinct ones).

The product of its digits is 136080, while the sum is 45.

The square root of 1989765 is about 1410.5903019658. The cubic root of 1989765 is about 125.7768157909.

The spelling of 1989765 in words is "one million, nine hundred eighty-nine thousand, seven hundred sixty-five".