20011099981 has 2 divisors, whose sum is σ = 20011099982. Its totient is φ = 20011099980.

The previous prime is 20011099963. The next prime is 20011100023. The reversal of 20011099981 is 18999011002.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 17905116100 + 2105983881 = 133810^2 + 45891^2 .

It is a cyclic number.

It is not a de Polignac number, because 20011099981 - 2⁵ = 20011099949 is a prime.

It is a super-2 number, since 2×20011099981² (a number of 21 digits) contains 22 as substring.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (20011099081) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10005549990 + 10005549991.

It is an arithmetic number, because the mean of its divisors is an integer number (10005549991).

Almost surely, 2^20011099981 is an apocalyptic number.

It is an amenable number.

20011099981 is a deficient number, since it is larger than the sum of its proper divisors (1).

20011099981 is an equidigital number, since it uses as much as digits as its factorization.

20011099981 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 11664, while the sum is 40.

The spelling of 20011099981 in words is "twenty billion, eleven million, ninety-nine thousand, nine hundred eighty-one".