200121220021 has 4 divisors (see below), whose sum is σ = 200123162892. Its totient is φ = 200119277152.

The previous prime is 200121220001. The next prime is 200121220069. The reversal of 200121220021 is 120022121002.

It is a happy number.

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 146834576100 + 53286643921 = 383190^2 + 230839^2 .

It is a cyclic number.

It is not a de Polignac number, because 200121220021 - 2¹¹ = 200121217973 is a prime.

It is a Duffinian number.

It is a junction number, because it is equal to n+sod(n) for n = 200121219983 and 200121220010.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (200121220001) 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, 807736 + ... + 1026001.

It is an arithmetic number, because the mean of its divisors is an integer number (50030790723).

Almost surely, 2^200121220021 is an apocalyptic number.

It is an amenable number.

200121220021 is a deficient number, since it is larger than the sum of its proper divisors (1942871).

200121220021 is a wasteful number, since it uses less digits than its factorization.

200121220021 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1942870.

The product of its (nonzero) digits is 32, while the sum is 13.

Adding to 200121220021 its reverse (120022121002), we get a palindrome (320143341023).

The spelling of 200121220021 in words is "two hundred billion, one hundred twenty-one million, two hundred twenty thousand, twenty-one".