200121121021 has 4 divisors (see below), whose sum is σ = 200688036732.
Its totient is φ = 199554205312.
The previous prime is 200121120989. The next prime is 200121121049. The reversal of 200121121021 is 120121121002.
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 82618879225 + 117502241796 = 287435^2 + 342786^2
It is a cyclic number.
It is not a de Polignac number, because 200121121021 - 25 = 200121120989 is a prime.
It is a Duffinian number.
It is a junction number, because it is equal to n+sod(n) for n = 200121120992 and 200121121010.
It is a congruent number.
It is not an unprimeable number, because it can be changed into a prime (200121121051) 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, 283457326 + ... + 283458031.
It is an arithmetic number, because the mean of its divisors is an integer number (50172009183).
Almost surely, 2200121121021 is an apocalyptic number.
It is an amenable number.
200121121021 is a deficient number, since it is larger than the sum of its proper divisors (566915711).
200121121021 is an equidigital number, since it uses as much as digits as its factorization.
200121121021 is an evil number, because the sum of its binary digits is even.
The sum of its prime factors is 566915710.
The product of its (nonzero) digits is 16, while the sum is 13.
Adding to 200121121021 its reverse (120121121002), we get a palindrome (320242242023).
The spelling of 200121121021 in words is "two hundred billion, one hundred twenty-one million, one hundred twenty-one thousand, twenty-one".