20136821 has 8 divisors (see below), whose sum is σ = 20628864. Its totient is φ = 19647520.

The previous prime is 20136811. The next prime is 20136841. The reversal of 20136821 is 12863102.

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

It is a cyclic number.

It is not a de Polignac number, because 20136821 - 2¹⁴ = 20120437 is a prime.

It is a Curzon number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (20136811) 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, 26081 + ... + 26841.

It is an arithmetic number, because the mean of its divisors is an integer number (2578608).

Almost surely, 2^20136821 is an apocalyptic number.

It is an amenable number.

20136821 is a deficient number, since it is larger than the sum of its proper divisors (492043).

20136821 is an equidigital number, since it uses as much as digits as its factorization.

20136821 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1371.

The product of its (nonzero) digits is 576, while the sum is 23.

The square root of 20136821 is about 4487.4069349681. The cubic root of 20136821 is about 272.0593377247.

Adding to 20136821 its reverse (12863102), we get a palindrome (32999923).

The spelling of 20136821 in words is "twenty million, one hundred thirty-six thousand, eight hundred twenty-one".