1125561809 has 2 divisors, whose sum is σ = 1125561810. Its totient is φ = 1125561808.

The previous prime is 1125561803. The next prime is 1125561817. The reversal of 1125561809 is 9081655211.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 970011025 + 155550784 = 31145^2 + 12472^2 .

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-1125561809 is a prime.

It is not a weakly prime, because it can be changed into another prime (1125561803) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 562780904 + 562780905.

It is an arithmetic number, because the mean of its divisors is an integer number (562780905).

Almost surely, 2^1125561809 is an apocalyptic number.

It is an amenable number.

1125561809 is a deficient number, since it is larger than the sum of its proper divisors (1).

1125561809 is an equidigital number, since it uses as much as digits as its factorization.

1125561809 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 21600, while the sum is 38.

The square root of 1125561809 is about 33549.3935712704. The cubic root of 1125561809 is about 1040.2150100945.

The spelling of 1125561809 in words is "one billion, one hundred twenty-five million, five hundred sixty-one thousand, eight hundred nine".