20210220220021 has 4 divisors (see below), whose sum is σ = 21764852544652. Its totient is φ = 18655587895392.

The previous prime is 20210220219991. The next prime is 20210220220087. The reversal of 20210220220021 is 12002202201202.

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 12541613119396 + 7668607100625 = 3541414^2 + 2769225^2 .

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-20210220220021 is a prime.

It is a Duffinian number.

It is a junction number, because it is equal to n+sod(n) for n = 20210220219977 and 20210220220004.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (20210220223021) 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, 777316162296 + ... + 777316162321.

It is an arithmetic number, because the mean of its divisors is an integer number (5441213136163).

Almost surely, 2^{20210220220021} is an apocalyptic number.

It is an amenable number.

20210220220021 is a deficient number, since it is larger than the sum of its proper divisors (1554632324631).

20210220220021 is a wasteful number, since it uses less digits than its factorization.

20210220220021 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1554632324630.

The product of its (nonzero) digits is 128, while the sum is 16.

Adding to 20210220220021 its reverse (12002202201202), we get a palindrome (32212422421223).

The spelling of 20210220220021 in words is "twenty trillion, two hundred ten billion, two hundred twenty million, two hundred twenty thousand, twenty-one".