20213121421 has 4 divisors (see below), whose sum is σ = 20497813344. Its totient is φ = 19928429500.

The previous prime is 20213121403. The next prime is 20213121437. The reversal of 20213121421 is 12412131202.

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.

It is a cyclic number.

It is not a de Polignac number, because 20213121421 - 2⁷ = 20213121293 is a prime.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (20213125421) 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, 142345855 + ... + 142345996.

It is an arithmetic number, because the mean of its divisors is an integer number (5124453336).

Almost surely, 2^20213121421 is an apocalyptic number.

It is an amenable number.

20213121421 is a deficient number, since it is larger than the sum of its proper divisors (284691923).

20213121421 is an equidigital number, since it uses as much as digits as its factorization.

20213121421 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 284691922.

The product of its (nonzero) digits is 192, while the sum is 19.

Adding to 20213121421 its reverse (12412131202), we get a palindrome (32625252623).

The spelling of 20213121421 in words is "twenty billion, two hundred thirteen million, one hundred twenty-one thousand, four hundred twenty-one".