256121606261 has 8 divisors (see below), whose sum is σ = 260967965184. Its totient is φ = 251275761360.

The previous prime is 256121606249. The next prime is 256121606281. The reversal of 256121606261 is 162606121652.

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 256121606261 - 2¹⁰ = 256121605237 is a prime.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (256121606281) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 964580 + ... + 1201106.

It is an arithmetic number, because the mean of its divisors is an integer number (32620995648).

Almost surely, 2^256121606261 is an apocalyptic number.

It is an amenable number.

256121606261 is a deficient number, since it is larger than the sum of its proper divisors (4846358923).

256121606261 is a wasteful number, since it uses less digits than its factorization.

256121606261 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 257011.

The product of its (nonzero) digits is 51840, while the sum is 38.

The spelling of 256121606261 in words is "two hundred fifty-six billion, one hundred twenty-one million, six hundred six thousand, two hundred sixty-one".