200121100021021 has 2 divisors, whose sum is σ = 200121100021022. Its totient is φ = 200121100021020.

The previous prime is 200121100021019. The next prime is 200121100021081. The reversal of 200121100021021 is 120120001121002.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 131177737291225 + 68943362729796 = 11453285^2 + 8303214^2 .

It is a cyclic number.

It is not a de Polignac number, because 200121100021021 - 2¹ = 200121100021019 is a prime.

Together with 200121100021019, it forms a pair of twin primes.

It is a junction number, because it is equal to n+sod(n) for n = 200121100020992 and 200121100021010.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (200121100021081) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 100060550010510 + 100060550010511.

It is an arithmetic number, because the mean of its divisors is an integer number (100060550010511).

Almost surely, 2^{200121100021021} is an apocalyptic number.

It is an amenable number.

200121100021021 is a deficient number, since it is larger than the sum of its proper divisors (1).

200121100021021 is an equidigital number, since it uses as much as digits as its factorization.

200121100021021 is an evil number, because the sum of its binary digits is even.

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

Adding to 200121100021021 its reverse (120120001121002), we get a palindrome (320241101142023).

The spelling of 200121100021021 in words is "two hundred trillion, one hundred twenty-one billion, one hundred million, twenty-one thousand, twenty-one".