256698691 has 16 divisors (see below), whose sum is σ = 287733600. Its totient is φ = 227824128.

The previous prime is 256698679. The next prime is 256698703. The reversal of 256698691 is 196896652.

It is an interprime number because it is at equal distance from previous prime (256698679) and next prime (256698703).

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-256698691 is a prime.

It is a super-2 number, since 2×256698691² = 131788435922226962, which contains 22 as substring.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (256698661) by changing a digit.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 15145 + ... + 27253.

It is an arithmetic number, because the mean of its divisors is an integer number (17983350).

Almost surely, 2^256698691 is an apocalyptic number.

256698691 is a deficient number, since it is larger than the sum of its proper divisors (31034909).

256698691 is a wasteful number, since it uses less digits than its factorization.

256698691 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 12198.

The product of its digits is 1399680, while the sum is 52.

The square root of 256698691 is about 16021.8192163062. The cubic root of 256698691 is about 635.5375537794.

The spelling of 256698691 in words is "two hundred fifty-six million, six hundred ninety-eight thousand, six hundred ninety-one".