1091605 has 8 divisors (see below), whose sum is σ = 1316952. Its totient is φ = 868608.

The previous prime is 1091591. The next prime is 1091609. The reversal of 1091605 is 5061901.

It can be written as a sum of positive squares in 4 ways, for example, as 14161 + 1077444 = 119^2 + 1038^2 .

It is a sphenic number, since it is the product of 3 distinct primes.

It is a cyclic number.

It is not a de Polignac number, because 1091605 - 2⁷ = 1091477 is a prime.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (1091609) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (7) of ones.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 697 + ... + 1633.

It is an arithmetic number, because the mean of its divisors is an integer number (164619).

2^1091605 is an apocalyptic number.

It is an amenable number.

1091605 is a deficient number, since it is larger than the sum of its proper divisors (225347).

1091605 is an equidigital number, since it uses as much as digits as its factorization.

1091605 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1175.

The product of its (nonzero) digits is 270, while the sum is 22.

The square root of 1091605 is about 1044.7990237361. The cubic root of 1091605 is about 102.9647348403.

The spelling of 1091605 in words is "one million, ninety-one thousand, six hundred five".