20001202021 has 4 divisors (see below), whose sum is σ = 20030746572. Its totient is φ = 19971657472.

The previous prime is 20001201991. The next prime is 20001202031. The reversal of 20001202021 is 12020210002.

It is a semiprime because it is the product of two primes, and also an emirpimes, since its reverse is a distinct semiprime: 12020210002 = 2 ⋅6010105001.

It can be written as a sum of positive squares in 2 ways, for example, as 19891999521 + 109202500 = 141039^2 + 10450^2 .

It is a cyclic number.

It is not a de Polignac number, because 20001202021 - 2⁹ = 20001201509 is a prime.

It is a Duffinian number.

It is a junction number, because it is equal to n+sod(n) for n = 20001201989 and 20001202007.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (20001202031) 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, 14771260 + ... + 14772613.

It is an arithmetic number, because the mean of its divisors is an integer number (5007686643).

Almost surely, 2^20001202021 is an apocalyptic number.

It is an amenable number.

20001202021 is a deficient number, since it is larger than the sum of its proper divisors (29544551).

20001202021 is an equidigital number, since it uses as much as digits as its factorization.

20001202021 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 29544550.

The product of its (nonzero) digits is 16, while the sum is 10.

Adding to 20001202021 its reverse (12020210002), we get a palindrome (32021412023).

It can be divided in two parts, 2000 and 1202021, that added together give a palindrome (1204021).

The spelling of 20001202021 in words is "twenty billion, one million, two hundred two thousand, twenty-one".