256761643677240 has 128 divisors (see below), whose sum is σ = 831329278295040. Its totient is φ = 63066358688256.

The previous prime is 256761643677211. The next prime is 256761643677299. The reversal of 256761643677240 is 42776346167652.

It is a congruent number.

It is an unprimeable number.

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 31 ways as a sum of consecutive naturals, for example, 177021562 + ... + 178466121.

It is an arithmetic number, because the mean of its divisors is an integer number (6494759986680).

Almost surely, 2^{256761643677240} is an apocalyptic number.

256761643677240 is a gapful number since it is divisible by the number (20) formed by its first and last digit.

It is an amenable number.

256761643677240 is an abundant number, since it is smaller than the sum of its proper divisors (574567634617800).

It is a pseudoperfect number, because it is the sum of a subset of its proper divisors.

256761643677240 is a wasteful number, since it uses less digits than its factorization.

256761643677240 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 355488173 (or 355488169 counting only the distinct ones).

The product of its (nonzero) digits is 426746880, while the sum is 66.

The spelling of 256761643677240 in words is "two hundred fifty-six trillion, seven hundred sixty-one billion, six hundred forty-three million, six hundred seventy-seven thousand, two hundred forty".