20121020110021 has 4 divisors (see below), whose sum is σ = 20127194099200. Its totient is φ = 20114846120844.

The previous prime is 20121020110007. The next prime is 20121020110073. The reversal of 20121020110021 is 12001102012102.

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 20121020110021 - 2¹¹ = 20121020107973 is a prime.

It is a Duffinian number.

It is a junction number, because it is equal to n+sod(n) for n = 20121020109983 and 20121020110010.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (20121023110021) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 3086989701 + ... + 3086996218.

It is an arithmetic number, because the mean of its divisors is an integer number (5031798524800).

Almost surely, 2^{20121020110021} is an apocalyptic number.

It is an amenable number.

20121020110021 is a deficient number, since it is larger than the sum of its proper divisors (6173989179).

20121020110021 is an equidigital number, since it uses as much as digits as its factorization.

20121020110021 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 6173989178.

The product of its (nonzero) digits is 16, while the sum is 13.

Adding to 20121020110021 its reverse (12001102012102), we get a palindrome (32122122122123).

The spelling of 20121020110021 in words is "twenty trillion, one hundred twenty-one billion, twenty million, one hundred ten thousand, twenty-one".