11009999981 has 2 divisors, whose sum is σ = 11009999982. Its totient is φ = 11009999980.

The previous prime is 11009999953. The next prime is 11010000013. The reversal of 11009999981 is 18999990011.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 10073333956 + 936666025 = 100366^2 + 30605^2 .

It is a cyclic number.

It is not a de Polignac number, because 11009999981 - 2¹⁰ = 11009998957 is a prime.

It is a super-2 number, since 2×11009999981² (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 (11009999921) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 5504999990 + 5504999991.

It is an arithmetic number, because the mean of its divisors is an integer number (5504999991).

Almost surely, 2^11009999981 is an apocalyptic number.

It is an amenable number.

11009999981 is a deficient number, since it is larger than the sum of its proper divisors (1).

11009999981 is an equidigital number, since it uses as much as digits as its factorization.

11009999981 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 472392, while the sum is 56.

The spelling of 11009999981 in words is "eleven billion, nine million, nine hundred ninety-nine thousand, nine hundred eighty-one".