1011109991921 has 2 divisors, whose sum is σ = 1011109991922. Its totient is φ = 1011109991920.

The previous prime is 1011109991909. The next prime is 1011109991963. The reversal of 1011109991921 is 1291999011101.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 927725344225 + 83384647696 = 963185^2 + 288764^2 .

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-1011109991921 is a prime.

It is not a weakly prime, because it can be changed into another prime (1011109990921) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (23) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 505554995960 + 505554995961.

It is an arithmetic number, because the mean of its divisors is an integer number (505554995961).

Almost surely, 2^{1011109991921} is an apocalyptic number.

It is an amenable number.

1011109991921 is a deficient number, since it is larger than the sum of its proper divisors (1).

1011109991921 is an equidigital number, since it uses as much as digits as its factorization.

1011109991921 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 13122, while the sum is 44.

The spelling of 1011109991921 in words is "one trillion, eleven billion, one hundred nine million, nine hundred ninety-one thousand, nine hundred twenty-one".