256006691 has 8 divisors (see below), whose sum is σ = 260642544. Its totient is φ = 251385120.

The previous prime is 256006687. The next prime is 256006717. The reversal of 256006691 is 196600652.

It is a happy number.

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 256006691 - 2² = 256006687 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (256006601) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 36620 + ... + 43046.

It is an arithmetic number, because the mean of its divisors is an integer number (32580318).

Almost surely, 2^256006691 is an apocalyptic number.

256006691 is a deficient number, since it is larger than the sum of its proper divisors (4635853).

256006691 is an equidigital number, since it uses as much as digits as its factorization.

256006691 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 7141.

The product of its (nonzero) digits is 19440, while the sum is 35.

The square root of 256006691 is about 16000.2090923838. The cubic root of 256006691 is about 634.9659526664.

The spelling of 256006691 in words is "two hundred fifty-six million, six thousand, six hundred ninety-one".