1091509 has 2 divisors, whose sum is σ = 1091510. Its totient is φ = 1091508.

The previous prime is 1091477. The next prime is 1091521. The reversal of 1091509 is 9051901.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 819025 + 272484 = 905^2 + 522^2 .

It is a cyclic number.

It is not a de Polignac number, because 1091509 - 2⁵ = 1091477 is a prime.

It is an Ulam number.

1091509 is a lucky number.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (1091549) 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, 545754 + 545755.

It is an arithmetic number, because the mean of its divisors is an integer number (545755).

2^1091509 is an apocalyptic number.

It is an amenable number.

1091509 is a deficient number, since it is larger than the sum of its proper divisors (1).

1091509 is an equidigital number, since it uses as much as digits as its factorization.

1091509 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 405, while the sum is 25.

The square root of 1091509 is about 1044.7530808761. The cubic root of 1091509 is about 102.9617163784.

It can be divided in two parts, 1091 and 509, that added together give a square (1600 = 40²).

The spelling of 1091509 in words is "one million, ninety-one thousand, five hundred nine".