256540245261 has 64 divisors (see below), whose sum is σ = 364986445824. Its totient is φ = 159942182400.

The previous prime is 256540245223. The next prime is 256540245289. The reversal of 256540245261 is 162542045652.

It is a happy number.

It is not a de Polignac number, because 256540245261 - 2¹¹ = 256540243213 is a prime.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (256540245361) by changing a digit.

It is a polite number, since it can be written in 63 ways as a sum of consecutive naturals, for example, 449282106 + ... + 449282676.

It is an arithmetic number, because the mean of its divisors is an integer number (5702913216).

Almost surely, 2^256540245261 is an apocalyptic number.

It is an amenable number.

256540245261 is a deficient number, since it is larger than the sum of its proper divisors (108446200563).

256540245261 is a wasteful number, since it uses less digits than its factorization.

256540245261 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1274.

The product of its (nonzero) digits is 576000, while the sum is 42.

The spelling of 256540245261 in words is "two hundred fifty-six billion, five hundred forty million, two hundred forty-five thousand, two hundred sixty-one".