256603665 has 8 divisors (see below), whose sum is σ = 410565888. Its totient is φ = 136855280.

The previous prime is 256603651. The next prime is 256603681. The reversal of 256603665 is 566306652.

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

It is not a de Polignac number, because 256603665 - 2⁶ = 256603601 is a prime.

It is an unprimeable number.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 8553441 + ... + 8553470.

It is an arithmetic number, because the mean of its divisors is an integer number (51320736).

Almost surely, 2^256603665 is an apocalyptic number.

It is an amenable number.

256603665 is a deficient number, since it is larger than the sum of its proper divisors (153962223).

256603665 is a wasteful number, since it uses less digits than its factorization.

256603665 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 17106919.

The product of its (nonzero) digits is 194400, while the sum is 39.

The square root of 256603665 is about 16018.8534233883. The cubic root of 256603665 is about 635.4591219481.

The spelling of 256603665 in words is "two hundred fifty-six million, six hundred three thousand, six hundred sixty-five".