20011010021 has 2 divisors, whose sum is σ = 20011010022. Its totient is φ = 20011010020.

The previous prime is 20011010017. The next prime is 20011010023. The reversal of 20011010021 is 12001011002.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 13991577796 + 6019432225 = 118286^2 + 77585^2 .

It is a cyclic number.

It is not a de Polignac number, because 20011010021 - 2² = 20011010017 is a prime.

It is a Sophie Germain prime.

Together with 20011010023, it forms a pair of twin primes.

It is a Chen prime.

It is a Curzon number.

It is a junction number, because it is equal to n+sod(n) for n = 20011009990 and 20011010008.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (20011010023) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10005505010 + 10005505011.

It is an arithmetic number, because the mean of its divisors is an integer number (10005505011).

Almost surely, 2^20011010021 is an apocalyptic number.

It is an amenable number.

20011010021 is a deficient number, since it is larger than the sum of its proper divisors (1).

20011010021 is an equidigital number, since it uses as much as digits as its factorization.

20011010021 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 4, while the sum is 8.

Adding to 20011010021 its reverse (12001011002), we get a palindrome (32012021023).

The spelling of 20011010021 in words is "twenty billion, eleven million, ten thousand, twenty-one".