261507551056 has 40 divisors (see below), whose sum is σ = 517515805440. Its totient is φ = 127955781504.

The previous prime is 261507551033. The next prime is 261507551077. The reversal of 261507551056 is 650155705162.

It is a congruent number.

It is an unprimeable number.

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, 7929930 + ... + 7962838.

It is an arithmetic number, because the mean of its divisors is an integer number (12937895136).

Almost surely, 2^261507551056 is an apocalyptic number.

It is an amenable number.

261507551056 is a deficient number, since it is larger than the sum of its proper divisors (256008254384).

261507551056 is a wasteful number, since it uses less digits than its factorization.

261507551056 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 43531 (or 43525 counting only the distinct ones).

The product of its (nonzero) digits is 315000, while the sum is 43.

The spelling of 261507551056 in words is "two hundred sixty-one billion, five hundred seven million, five hundred fifty-one thousand, fifty-six".