2564491309 has 4 divisors (see below), whose sum is σ = 2577378400. Its totient is φ = 2551604220.

The previous prime is 2564491291. The next prime is 2564491331. The reversal of 2564491309 is 9031944652.

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 2564491309 - 2²¹ = 2562394157 is a prime.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (2564491339) 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, 6443247 + ... + 6443644.

It is an arithmetic number, because the mean of its divisors is an integer number (644344600).

Almost surely, 2^2564491309 is an apocalyptic number.

It is an amenable number.

2564491309 is a deficient number, since it is larger than the sum of its proper divisors (12887091).

2564491309 is a wasteful number, since it uses less digits than its factorization.

2564491309 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 12887090.

The product of its (nonzero) digits is 233280, while the sum is 43.

The square root of 2564491309 is about 50640.8067570018. The cubic root of 2564491309 is about 1368.7802931127.

The spelling of 2564491309 in words is "two billion, five hundred sixty-four million, four hundred ninety-one thousand, three hundred nine".