256505747 has 8 divisors (see below), whose sum is σ = 261584640. Its totient is φ = 251467720.

The previous prime is 256505731. The next prime is 256505791. The reversal of 256505747 is 747505652.

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 256505747 - 2⁴ = 256505731 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (256505797) 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, 2618 + ... + 22800.

It is an arithmetic number, because the mean of its divisors is an integer number (32698080).

Almost surely, 2^256505747 is an apocalyptic number.

256505747 is a deficient number, since it is larger than the sum of its proper divisors (5078893).

256505747 is a wasteful number, since it uses less digits than its factorization.

256505747 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 20433.

The product of its (nonzero) digits is 294000, while the sum is 41.

The square root of 256505747 is about 16015.7967956640. The cubic root of 256505747 is about 635.3782828812.

The spelling of 256505747 in words is "two hundred fifty-six million, five hundred five thousand, seven hundred forty-seven".