20212120220021 has 4 divisors (see below), whose sum is σ = 20212560914700. Its totient is φ = 20211679525344.

The previous prime is 20212120219997. The next prime is 20212120220099. The reversal of 20212120220021 is 12002202121202.

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 14026627905796 + 6185492314225 = 3745214^2 + 2487065^2 .

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-20212120220021 is a prime.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (20212120220921) 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, 220278536 + ... + 220370273.

It is an arithmetic number, because the mean of its divisors is an integer number (5053140228675).

Almost surely, 2^{20212120220021} is an apocalyptic number.

It is an amenable number.

20212120220021 is a deficient number, since it is larger than the sum of its proper divisors (440694679).

20212120220021 is an equidigital number, since it uses as much as digits as its factorization.

20212120220021 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 440694678.

The product of its (nonzero) digits is 128, while the sum is 17.

Adding to 20212120220021 its reverse (12002202121202), we get a palindrome (32214322341223).

The spelling of 20212120220021 in words is "twenty trillion, two hundred twelve billion, one hundred twenty million, two hundred twenty thousand, twenty-one".