256365009 has 18 divisors (see below), whose sum is σ = 382648578. Its totient is φ = 165391200.

The previous prime is 256365001. The next prime is 256365013. The reversal of 256365009 is 900563652.

It can be written as a sum of positive squares in only one way, i.e., 252905409 + 3459600 = 15903^2 + 1860^2 .

It is not a de Polignac number, because 256365009 - 2³ = 256365001 is a prime.

It is a Smith number, since the sum of its digits (36) coincides with the sum of the digits of its prime factors.

It is a Curzon number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (256365001) by changing a digit.

It is a polite number, since it can be written in 17 ways as a sum of consecutive naturals, for example, 6172 + ... + 23469.

Almost surely, 2^256365009 is an apocalyptic number.

It is an amenable number.

256365009 is a deficient number, since it is larger than the sum of its proper divisors (126283569).

256365009 is a wasteful number, since it uses less digits than its factorization.

256365009 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 29709 (or 29675 counting only the distinct ones).

The product of its (nonzero) digits is 48600, while the sum is 36.

The square root of 256365009 is about 16011.4024682412. The cubic root of 256365009 is about 635.2620564687.

The spelling of 256365009 in words is "two hundred fifty-six million, three hundred sixty-five thousand, nine".