20021121100121 has 4 divisors (see below), whose sum is σ = 20021317987044. Its totient is φ = 20020924213200.

The previous prime is 20021121100109. The next prime is 20021121100171. The reversal of 20021121100121 is 12100112112002.

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 7118197320025 + 12902923780096 = 2667995^2 + 3592064^2 .

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-20021121100121 is a prime.

It is a Duffinian number.

It is a junction number, because it is equal to n+sod(n) for n = 20021121100096 and 20021121100105.

It is not an unprimeable number, because it can be changed into a prime (20021121100171) 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, 98290850 + ... + 98494331.

It is an arithmetic number, because the mean of its divisors is an integer number (5005329496761).

Almost surely, 2^{20021121100121} is an apocalyptic number.

It is an amenable number.

20021121100121 is a deficient number, since it is larger than the sum of its proper divisors (196886923).

20021121100121 is a wasteful number, since it uses less digits than its factorization.

20021121100121 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 196886922.

The product of its (nonzero) digits is 16, while the sum is 14.

Adding to 20021121100121 its reverse (12100112112002), we get a palindrome (32121233212123).

The spelling of 20021121100121 in words is "twenty trillion, twenty-one billion, one hundred twenty-one million, one hundred thousand, one hundred twenty-one".