256805729 has 8 divisors (see below), whose sum is σ = 270547680. Its totient is φ = 243086400.

The previous prime is 256805711. The next prime is 256805743. The reversal of 256805729 is 927508652.

It is a sphenic number, since it is the product of 3 distinct primes.

It is a cyclic number.

It is not a de Polignac number, because 256805729 - 2¹⁶ = 256740193 is a prime.

It is a Duffinian number.

It is a self number, because there is not a number n which added to its sum of digits gives 256805729.

It is not an unprimeable number, because it can be changed into a prime (256805429) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 20894 + ... + 30824.

It is an arithmetic number, because the mean of its divisors is an integer number (33818460).

Almost surely, 2^256805729 is an apocalyptic number.

It is an amenable number.

256805729 is a deficient number, since it is larger than the sum of its proper divisors (13741951).

256805729 is a wasteful number, since it uses less digits than its factorization.

256805729 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 11311.

The product of its (nonzero) digits is 302400, while the sum is 44.

The square root of 256805729 is about 16025.1592503788. The cubic root of 256805729 is about 635.6258768056.

The spelling of 256805729 in words is "two hundred fifty-six million, eight hundred five thousand, seven hundred twenty-nine".