64256509 has 4 divisors (see below), whose sum is σ = 64279516. Its totient is φ = 64233504.

The previous prime is 64256501. The next prime is 64256513. The reversal of 64256509 is 90565246.

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 47265625 + 16990884 = 6875^2 + 4122^2 .

It is a cyclic number.

It is not a de Polignac number, because 64256509 - 2³ = 64256501 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 (64256501) 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, 6624 + ... + 13129.

It is an arithmetic number, because the mean of its divisors is an integer number (16069879).

Almost surely, 2^64256509 is an apocalyptic number.

It is an amenable number.

64256509 is a deficient number, since it is larger than the sum of its proper divisors (23007).

64256509 is a wasteful number, since it uses less digits than its factorization.

64256509 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 23006.

The product of its (nonzero) digits is 64800, while the sum is 37.

The square root of 64256509 is about 8016.0157809226. The cubic root of 64256509 is about 400.5336813938.

The spelling of 64256509 in words is "sixty-four million, two hundred fifty-six thousand, five hundred nine".