20384821 has 4 divisors (see below), whose sum is σ = 20395552. Its totient is φ = 20374092.

The previous prime is 20384809. The next prime is 20384851. The reversal of 20384821 is 12848302.

It is a semiprime because it is the product of two primes, and also a Blum integer, because the two primes are equal to 3 mod 4, and also a brilliant number, because the two primes have the same length.

It is a cyclic number.

It is not a de Polignac number, because 20384821 - 2⁵ = 20384789 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 20384821.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (20384851) 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, 1665 + ... + 6598.

It is an arithmetic number, because the mean of its divisors is an integer number (5098888).

Almost surely, 2^20384821 is an apocalyptic number.

It is an amenable number.

20384821 is a deficient number, since it is larger than the sum of its proper divisors (10731).

20384821 is an equidigital number, since it uses as much as digits as its factorization.

20384821 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 10730.

The product of its (nonzero) digits is 3072, while the sum is 28.

The square root of 20384821 is about 4514.9552600220. The cubic root of 20384821 is about 273.1716551620.

It can be divided in two parts, 2038 and 4821, that added together give a cube (6859 = 19³).

The spelling of 20384821 in words is "twenty million, three hundred eighty-four thousand, eight hundred twenty-one".