20011021109 has 2 divisors, whose sum is σ = 20011021110. Its totient is φ = 20011021108.

The previous prime is 20011021099. The next prime is 20011021153. The reversal of 20011021109 is 90112011002.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 19593840484 + 417180625 = 139978^2 + 20425^2 .

It is a cyclic number.

It is not a de Polignac number, because 20011021109 - 2⁸ = 20011020853 is a prime.

It is a Sophie Germain prime.

It is a Curzon number.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (20011020109) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10005510554 + 10005510555.

It is an arithmetic number, because the mean of its divisors is an integer number (10005510555).

Almost surely, 2^20011021109 is an apocalyptic number.

It is an amenable number.

20011021109 is a deficient number, since it is larger than the sum of its proper divisors (1).

20011021109 is an equidigital number, since it uses as much as digits as its factorization.

20011021109 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 36, while the sum is 17.

The spelling of 20011021109 in words is "twenty billion, eleven million, twenty-one thousand, one hundred nine".