20243421021 has 16 divisors (see below), whose sum is σ = 27602052800. Its totient is φ = 13192917120.

The previous prime is 20243421017. The next prime is 20243421101. The reversal of 20243421021 is 12012434202.

It is not a de Polignac number, because 20243421021 - 2² = 20243421017 is a prime.

It is a Duffinian number.

It is a Curzon number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (20243221021) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (19) of ones.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 309496 + ... + 369153.

It is an arithmetic number, because the mean of its divisors is an integer number (1725128300).

Almost surely, 2^20243421021 is an apocalyptic number.

It is an amenable number.

20243421021 is a deficient number, since it is larger than the sum of its proper divisors (7358631779).

20243421021 is a wasteful number, since it uses less digits than its factorization.

20243421021 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 678876.

The product of its (nonzero) digits is 768, while the sum is 21.

Adding to 20243421021 its reverse (12012434202), we get a palindrome (32255855223).

The spelling of 20243421021 in words is "twenty billion, two hundred forty-three million, four hundred twenty-one thousand, twenty-one".