20010020021 has 4 divisors (see below), whose sum is σ = 20018419392. Its totient is φ = 20001620652.

The previous prime is 20010020003. The next prime is 20010020053. The reversal of 20010020021 is 12002001002.

It is a semiprime because it is the product of two primes, and also a Blum integer, because the two primes are equal to 3 mod 4.

It is a cyclic number.

It is not a de Polignac number, because 20010020021 - 2³⁰ = 18936278197 is a prime.

It is a Duffinian number.

It is a junction number, because it is equal to n+sod(n) for n = 20010019990 and 20010020008.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (20010020071) 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, 4196111 + ... + 4200876.

It is an arithmetic number, because the mean of its divisors is an integer number (5004604848).

Almost surely, 2^20010020021 is an apocalyptic number.

It is an amenable number.

20010020021 is a deficient number, since it is larger than the sum of its proper divisors (8399371).

20010020021 is an equidigital number, since it uses as much as digits as its factorization.

20010020021 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 8399370.

The product of its (nonzero) digits is 8, while the sum is 8.

Adding to 20010020021 its reverse (12002001002), we get a palindrome (32012021023).

The spelling of 20010020021 in words is "twenty billion, ten million, twenty thousand, twenty-one".