20844421 has 4 divisors (see below), whose sum is σ = 22447852. Its totient is φ = 19240992.

The previous prime is 20844409. The next prime is 20844433. The reversal of 20844421 is 12444802.

It is a semiprime because it is the product of two primes.

It is an interprime number because it is at equal distance from previous prime (20844409) and next prime (20844433).

It can be written as a sum of positive squares in 2 ways, for example, as 11296321 + 9548100 = 3361^2 + 3090^2 .

It is a cyclic number.

It is not a de Polignac number, because 20844421 - 2⁵ = 20844389 is a prime.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (20844401) 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 3 ways as a sum of consecutive naturals, for example, 801696 + ... + 801721.

It is an arithmetic number, because the mean of its divisors is an integer number (5611963).

Almost surely, 2^20844421 is an apocalyptic number.

It is an amenable number.

20844421 is a deficient number, since it is larger than the sum of its proper divisors (1603431).

20844421 is a wasteful number, since it uses less digits than its factorization.

20844421 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1603430.

The product of its (nonzero) digits is 2048, while the sum is 25.

The square root of 20844421 is about 4565.5690773440. The cubic root of 20844421 is about 275.2094096423.

The spelling of 20844421 in words is "twenty million, eight hundred forty-four thousand, four hundred twenty-one".