20844689 has 4 divisors (see below), whose sum is σ = 20885220. Its totient is φ = 20804160.

The previous prime is 20844671. The next prime is 20844701. The reversal of 20844689 is 98644802.

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 15737089 + 5107600 = 3967^2 + 2260^2 .

It is a cyclic number.

It is not a de Polignac number, because 20844689 - 2⁸ = 20844433 is a prime.

It is a Duffinian number.

20844689 is a modest number, since divided by 4689 gives 2084 as remainder.

It is not an unprimeable number, because it can be changed into a prime (20844619) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 19484 + ... + 20525.

It is an arithmetic number, because the mean of its divisors is an integer number (5221305).

Almost surely, 2^20844689 is an apocalyptic number.

It is an amenable number.

20844689 is a deficient number, since it is larger than the sum of its proper divisors (40531).

20844689 is an equidigital number, since it uses as much as digits as its factorization.

20844689 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 40530.

The product of its (nonzero) digits is 110592, while the sum is 41.

The square root of 20844689 is about 4565.5984273696. The cubic root of 20844689 is about 275.2105891074.

It can be divided in two parts, 2084 and 4689, that multiplied together give a square (9771876 = 3126²).

The spelling of 20844689 in words is "twenty million, eight hundred forty-four thousand, six hundred eighty-nine".