256509942489545 has 16 divisors (see below), whose sum is σ = 308181053361792. Its totient is φ = 204961903372800.

The previous prime is 256509942489533. The next prime is 256509942489553. The reversal of 256509942489545 is 545984249905652.

It is not a de Polignac number, because 256509942489545 - 2⁴ = 256509942489529 is a prime.

It is a Duffinian number.

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (19) of ones.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 64620020 + ... + 68474570.

It is an arithmetic number, because the mean of its divisors is an integer number (19261315835112).

Almost surely, 2^{256509942489545} is an apocalyptic number.

It is an amenable number.

256509942489545 is a deficient number, since it is larger than the sum of its proper divisors (51671110872247).

256509942489545 is a wasteful number, since it uses less digits than its factorization.

256509942489545 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 3870512.

The product of its (nonzero) digits is 5598720000, while the sum is 77.

The spelling of 256509942489545 in words is "two hundred fifty-six trillion, five hundred nine billion, nine hundred forty-two million, four hundred eighty-nine thousand, five hundred forty-five".