20841909 has 8 divisors (see below), whose sum is σ = 30315552. Its totient is φ = 12631440.

The previous prime is 20841883. The next prime is 20841911. The reversal of 20841909 is 90914802.

It is a sphenic number, since it is the product of 3 distinct primes.

It is not a de Polignac number, because 20841909 - 2¹⁵ = 20809141 is a prime.

It is a Harshad number since it is a multiple of its sum of digits (33), and also a Moran number because the ratio is a prime number: 631573 = 20841909 / (2 + 0 + 8 + 4 + 1 + 9 + 0 + 9).

It is a Curzon number.

It is a self number, because there is not a number n which added to its sum of digits gives 20841909.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (20841959) 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 7 ways as a sum of consecutive naturals, for example, 315754 + ... + 315819.

It is an arithmetic number, because the mean of its divisors is an integer number (3789444).

Almost surely, 2^20841909 is an apocalyptic number.

It is an amenable number.

20841909 is a deficient number, since it is larger than the sum of its proper divisors (9473643).

20841909 is a wasteful number, since it uses less digits than its factorization.

20841909 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 631587.

The product of its (nonzero) digits is 5184, while the sum is 33.

The square root of 20841909 is about 4565.2939664385. The cubic root of 20841909 is about 275.1983538653.

It can be divided in two parts, 2084 and 1909, that added together give a palindrome (3993).

The spelling of 20841909 in words is "twenty million, eight hundred forty-one thousand, nine hundred nine".