20784421 has 8 divisors (see below), whose sum is σ = 25151040. Its totient is φ = 16767168.

The previous prime is 20784409. The next prime is 20784443. The reversal of 20784421 is 12448702.

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

It is not a de Polignac number, because 20784421 - 2⁵ = 20784389 is a prime.

It is a Duffinian number.

It is a self number, because there is not a number n which added to its sum of digits gives 20784421.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (20784451) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 87211 + ... + 87448.

It is an arithmetic number, because the mean of its divisors is an integer number (3143880).

Almost surely, 2^20784421 is an apocalyptic number.

It is an amenable number.

20784421 is a deficient number, since it is larger than the sum of its proper divisors (4366619).

20784421 is a wasteful number, since it uses less digits than its factorization.

20784421 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 174683.

The product of its (nonzero) digits is 3584, while the sum is 28.

The square root of 20784421 is about 4558.9934196048. The cubic root of 20784421 is about 274.9450953749.

The spelling of 20784421 in words is "twenty million, seven hundred eighty-four thousand, four hundred twenty-one".