1025809 has 4 divisors (see below), whose sum is σ = 1035504. Its totient is φ = 1016116.

The previous prime is 1025807. The next prime is 1025819. The reversal of 1025809 is 9085201.

It is a semiprime because it is the product of two primes, and also a Blum integer, because the two primes are equal to 3 mod 4, and also an emirpimes, since its reverse is a distinct semiprime: 9085201 = 31 ⋅293071.

It is a cyclic number.

It is not a de Polignac number, because 1025809 - 2¹ = 1025807 is a prime.

It is a Duffinian number.

It is a nialpdrome in base 16.

It is not an unprimeable number, because it can be changed into a prime (1025803) 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 in 3 ways as a sum of consecutive naturals, for example, 4687 + ... + 4900.

It is an arithmetic number, because the mean of its divisors is an integer number (258876).

2^1025809 is an apocalyptic number.

It is an amenable number.

1025809 is a deficient number, since it is larger than the sum of its proper divisors (9695).

1025809 is an equidigital number, since it uses as much as digits as its factorization.

1025809 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 9694.

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

The square root of 1025809 is about 1012.8222943834. The cubic root of 1025809 is about 100.8530031674.

The spelling of 1025809 in words is "one million, twenty-five thousand, eight hundred nine".