20984439 has 32 divisors (see below), whose sum is σ = 33269760. Its totient is φ = 11515392.

The previous prime is 20984437. The next prime is 20984461. The reversal of 20984439 is 93448902.

It is not a de Polignac number, because 20984439 - 2¹ = 20984437 is a prime.

It is a Smith number, since the sum of its digits (39) coincides with the sum of the digits of its prime factors. Since it is squarefree, it is also a hoax number.

It is a junction number, because it is equal to n+sod(n) for n = 20984397 and 20984406.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (20984437) 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 31 ways as a sum of consecutive naturals, for example, 87682 + ... + 87920.

It is an arithmetic number, because the mean of its divisors is an integer number (1039680).

Almost surely, 2^20984439 is an apocalyptic number.

20984439 is a deficient number, since it is larger than the sum of its proper divisors (12285321).

20984439 is a wasteful number, since it uses less digits than its factorization.

20984439 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 399.

The product of its (nonzero) digits is 62208, while the sum is 39.

The square root of 20984439 is about 4580.8775360186. The cubic root of 20984439 is about 275.8242553721.

It can be divided in two parts, 209 and 84439, that added together give a palindrome (84648).

The spelling of 20984439 in words is "twenty million, nine hundred eighty-four thousand, four hundred thirty-nine".