256673691 has 20 divisors (see below), whose sum is σ = 384604792. Its totient is φ = 170589888.

The previous prime is 256673689. The next prime is 256673723. The reversal of 256673691 is 196376652.

It is not a de Polignac number, because 256673691 - 2¹ = 256673689 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (256673611) by changing a digit.

It is a polite number, since it can be written in 19 ways as a sum of consecutive naturals, for example, 22596 + ... + 31998.

Almost surely, 2^256673691 is an apocalyptic number.

256673691 is a deficient number, since it is larger than the sum of its proper divisors (127931101).

256673691 is an equidigital number, since it uses as much as digits as its factorization.

256673691 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 9752 (or 9743 counting only the distinct ones).

The product of its digits is 408240, while the sum is 45.

The square root of 256673691 is about 16021.0390112502. The cubic root of 256673691 is about 635.5169213477.

The spelling of 256673691 in words is "two hundred fifty-six million, six hundred seventy-three thousand, six hundred ninety-one".