20123211021 has 16 divisors (see below), whose sum is σ = 26911108800.
Its totient is φ = 13375434240.
The previous prime is 20123211019. The next prime is 20123211029. The reversal of 20123211021 is 12011232102.
Adding to 20123211021 its reverse (12011232102), we get a palindrome (32134443123).
It is not a de Polignac number, because 20123211021 - 21 = 20123211019 is a prime.
It is a congruent number.
It is not an unprimeable number, because it can be changed into a prime (20123211029) by changing a digit.
It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 2627005 + ... + 2634653.
It is an arithmetic number, because the mean of its divisors is an integer number (1681944300).
Almost surely, 220123211021 is an apocalyptic number.
It is an amenable number.
20123211021 is a deficient number, since it is larger than the sum of its proper divisors (6787897779).
20123211021 is a wasteful number, since it uses less digits than its factorization.
20123211021 is an odious number, because the sum of its binary digits is odd.
The sum of its prime factors is 10156.
The product of its (nonzero) digits is 48, while the sum is 15.
The spelling of 20123211021 in words is "twenty billion, one hundred twenty-three million, two hundred eleven thousand, twenty-one".