20021021200121 has 4 divisors (see below), whose sum is σ = 20031687702372. Its totient is φ = 20010354697872.

The previous prime is 20021021200091. The next prime is 20021021200153. The reversal of 20021021200121 is 12100212012002.

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 7344430623721 + 12676590576400 = 2710061^2 + 3560420^2 .

It is a cyclic number.

It is not a de Polignac number, because 20021021200121 - 2³⁴ = 20003841330937 is a prime.

It is a Duffinian number.

It is a junction number, because it is equal to n+sod(n) for n = 20021021200096 and 20021021200105.

It is not an unprimeable number, because it can be changed into a prime (20021021200721) 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, 5333248310 + ... + 5333252063.

It is an arithmetic number, because the mean of its divisors is an integer number (5007921925593).

Almost surely, 2^{20021021200121} is an apocalyptic number.

It is an amenable number.

20021021200121 is a deficient number, since it is larger than the sum of its proper divisors (10666502251).

20021021200121 is a wasteful number, since it uses less digits than its factorization.

20021021200121 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 10666502250.

The product of its (nonzero) digits is 32, while the sum is 14.

Adding to 20021021200121 its reverse (12100212012002), we get a palindrome (32121233212123).

The spelling of 20021021200121 in words is "twenty trillion, twenty-one billion, twenty-one million, two hundred thousand, one hundred twenty-one".