2564809 has 4 divisors (see below), whose sum is σ = 2762116. Its totient is φ = 2367504.

The previous prime is 2564759. The next prime is 2564813. The reversal of 2564809 is 9084652.

It is a happy number.

It is a semiprime because it is the product of two primes.

It can be written as a sum of positive squares in 2 ways, for example, as 525625 + 2039184 = 725^2 + 1428^2 .

It is a cyclic number.

It is not a de Polignac number, because 2564809 - 2²¹ = 467657 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 (2564819) 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, 98634 + ... + 98659.

It is an arithmetic number, because the mean of its divisors is an integer number (690529).

2^2564809 is an apocalyptic number.

It is an amenable number.

2564809 is a deficient number, since it is larger than the sum of its proper divisors (197307).

2564809 is a wasteful number, since it uses less digits than its factorization.

2564809 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 197306.

The product of its (nonzero) digits is 17280, while the sum is 34.

The square root of 2564809 is about 1601.5021073979. The cubic root of 2564809 is about 136.8836812603.

The spelling of 2564809 in words is "two million, five hundred sixty-four thousand, eight hundred nine".