20210021002121 has 4 divisors (see below), whose sum is σ = 20210304694932. Its totient is φ = 20209737309312.

The previous prime is 20210021002069. The next prime is 20210021002139. The reversal of 20210021002121 is 12120012001202.

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 13168109606521 + 7041911395600 = 3628789^2 + 2653660^2 .

It is a cyclic number.

It is not a de Polignac number, because 20210021002121 - 2¹⁰ = 20210021001097 is a prime.

It is a Duffinian number.

It is a junction number, because it is equal to n+sod(n) for n = 20210021002096 and 20210021002105.

It is not an unprimeable number, because it can be changed into a prime (20210021002181) 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, 141739520 + ... + 141882033.

It is an arithmetic number, because the mean of its divisors is an integer number (5052576173733).

Almost surely, 2^{20210021002121} is an apocalyptic number.

It is an amenable number.

20210021002121 is a deficient number, since it is larger than the sum of its proper divisors (283692811).

20210021002121 is an equidigital number, since it uses as much as digits as its factorization.

20210021002121 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 283692810.

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

Adding to 20210021002121 its reverse (12120012001202), we get a palindrome (32330033003323).

The spelling of 20210021002121 in words is "twenty trillion, two hundred ten billion, twenty-one million, two thousand, one hundred twenty-one".