1991107 has 2 divisors, whose sum is σ = 1991108. Its totient is φ = 1991106.

The previous prime is 1991089. The next prime is 1991123. The reversal of 1991107 is 7011991.

It is a strong prime.

It is a cyclic number.

It is not a de Polignac number, because 1991107 - 2¹¹ = 1989059 is a prime.

It is a zygodrome in base 2.

It is not a weakly prime, because it can be changed into another prime (1991137) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 995553 + 995554.

It is an arithmetic number, because the mean of its divisors is an integer number (995554).

2^1991107 is an apocalyptic number.

1991107 is a deficient number, since it is larger than the sum of its proper divisors (1).

1991107 is an equidigital number, since it uses as much as digits as its factorization.

1991107 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 567, while the sum is 28.

The square root of 1991107 is about 1411.0659091623. The cubic root of 1991107 is about 125.8050862237.

The spelling of 1991107 in words is "one million, nine hundred ninety-one thousand, one hundred seven".