125000809 has 2 divisors, whose sum is σ = 125000810. Its totient is φ = 125000808.

The previous prime is 125000801. The next prime is 125000819. The reversal of 125000809 is 908000521.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 74874409 + 50126400 = 8653^2 + 7080^2 .

It is an emirp because it is prime and its reverse (908000521) is a distict prime.

It is a cyclic number.

It is not a de Polignac number, because 125000809 - 2³ = 125000801 is a prime.

It is not a weakly prime, because it can be changed into another prime (125000801) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 62500404 + 62500405.

It is an arithmetic number, because the mean of its divisors is an integer number (62500405).

Almost surely, 2^125000809 is an apocalyptic number.

It is an amenable number.

125000809 is a deficient number, since it is larger than the sum of its proper divisors (1).

125000809 is an equidigital number, since it uses as much as digits as its factorization.

125000809 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 720, while the sum is 25.

The square root of 125000809 is about 11180.3760670203. The cubic root of 125000809 is about 500.0010786643.

The spelling of 125000809 in words is "one hundred twenty-five million, eight hundred nine", and thus it is an aban number.