256749309731 has 8 divisors (see below), whose sum is σ = 260986924800. Its totient is φ = 252528956680.

The previous prime is 256749309679. The next prime is 256749309749. The reversal of 256749309731 is 137903947652.

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 256749309731 - 2⁶ = 256749309667 is a prime.

It is a super-2 number, since 2×256749309731² (a number of 24 digits) contains 22 as substring.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (256749309631) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (23) of ones.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 4285511 + ... + 4345008.

It is an arithmetic number, because the mean of its divisors is an integer number (32623365600).

Almost surely, 2^256749309731 is an apocalyptic number.

256749309731 is a deficient number, since it is larger than the sum of its proper divisors (4237615069).

256749309731 is an equidigital number, since it uses as much as digits as its factorization.

256749309731 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 8631009.

The product of its (nonzero) digits is 8573040, while the sum is 56.

The spelling of 256749309731 in words is "two hundred fifty-six billion, seven hundred forty-nine million, three hundred nine thousand, seven hundred thirty-one".