1091009291921 has 2 divisors, whose sum is σ = 1091009291922. Its totient is φ = 1091009291920.

The previous prime is 1091009291917. The next prime is 1091009291923. The reversal of 1091009291921 is 1291929001901.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 612719479696 + 478289812225 = 782764^2 + 691585^2 .

It is a cyclic number.

It is not a de Polignac number, because 1091009291921 - 2² = 1091009291917 is a prime.

Together with 1091009291923, it forms a pair of twin primes.

It is a Chen prime.

It is not a weakly prime, because it can be changed into another prime (1091009291923) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (19) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 545504645960 + 545504645961.

It is an arithmetic number, because the mean of its divisors is an integer number (545504645961).

Almost surely, 2^{1091009291921} is an apocalyptic number.

It is an amenable number.

1091009291921 is a deficient number, since it is larger than the sum of its proper divisors (1).

1091009291921 is an equidigital number, since it uses as much as digits as its factorization.

1091009291921 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 26244, while the sum is 44.

The spelling of 1091009291921 in words is "one trillion, ninety-one billion, nine million, two hundred ninety-one thousand, nine hundred twenty-one".