1309425809 has 4 divisors (see below), whose sum is σ = 1339877616. Its totient is φ = 1278974004.

The previous prime is 1309425787. The next prime is 1309425883. The reversal of 1309425809 is 9085249031.

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.

It is a cyclic number.

It is not a de Polignac number, because 1309425809 - 2¹² = 1309421713 is a prime.

It is a Duffinian number.

It is a Curzon number.

It is not an unprimeable number, because it can be changed into a prime (1309425889) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 15225839 + ... + 15225924.

It is an arithmetic number, because the mean of its divisors is an integer number (334969404).

Almost surely, 2^1309425809 is an apocalyptic number.

It is an amenable number.

1309425809 is a deficient number, since it is larger than the sum of its proper divisors (30451807).

1309425809 is an equidigital number, since it uses as much as digits as its factorization.

1309425809 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 30451806.

The product of its (nonzero) digits is 77760, while the sum is 41.

The square root of 1309425809 is about 36185.9891256271. The cubic root of 1309425809 is about 1094.0242926804.

The spelling of 1309425809 in words is "one billion, three hundred nine million, four hundred twenty-five thousand, eight hundred nine".