20021332421 has 4 divisors (see below), whose sum is σ = 20509657644. Its totient is φ = 19533007200.

The previous prime is 20021332411. The next prime is 20021332427. The reversal of 20021332421 is 12423312002.

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

It can be written as a sum of positive squares in 2 ways, for example, as 3979843396 + 16041489025 = 63086^2 + 126655^2 .

It is a cyclic number.

It is not a de Polignac number, because 20021332421 - 2¹⁴ = 20021316037 is a prime.

It is a Duffinian number.

It is a junction number, because it is equal to n+sod(n) for n = 20021332393 and 20021332402.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (20021332427) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 244162550 + ... + 244162631.

It is an arithmetic number, because the mean of its divisors is an integer number (5127414411).

Almost surely, 2^20021332421 is an apocalyptic number.

It is an amenable number.

20021332421 is a deficient number, since it is larger than the sum of its proper divisors (488325223).

20021332421 is an equidigital number, since it uses as much as digits as its factorization.

20021332421 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 488325222.

The product of its (nonzero) digits is 576, while the sum is 20.

Adding to 20021332421 its reverse (12423312002), we get a palindrome (32444644423).

The spelling of 20021332421 in words is "twenty billion, twenty-one million, three hundred thirty-two thousand, four hundred twenty-one".