256503621366617 has 16 divisors (see below), whose sum is σ = 271203684188160. Its totient is φ = 241925865631632.

The previous prime is 256503621366581. The next prime is 256503621366637. The reversal of 256503621366617 is 716663126305652.

It is a cyclic number.

It is not a de Polignac number, because 256503621366617 - 2⁴² = 252105574855513 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (256503621366637) 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, 28239353 + ... + 36200390.

It is an arithmetic number, because the mean of its divisors is an integer number (16950230261760).

Almost surely, 2^{256503621366617} is an apocalyptic number.

It is an amenable number.

256503621366617 is a deficient number, since it is larger than the sum of its proper divisors (14700062821543).

256503621366617 is a wasteful number, since it uses less digits than its factorization.

256503621366617 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 64440692.

The product of its (nonzero) digits is 48988800, while the sum is 59.

The spelling of 256503621366617 in words is "two hundred fifty-six trillion, five hundred three billion, six hundred twenty-one million, three hundred sixty-six thousand, six hundred seventeen".