261666505504306 has 32 divisors (see below), whose sum is σ = 462868650720000. Its totient is φ = 110882756720736.

The previous prime is 261666505504223. The next prime is 261666505504337. The reversal of 261666505504306 is 603405505666162.

It is an unprimeable number.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 2142849366 + ... + 2142971473.

It is an arithmetic number, because the mean of its divisors is an integer number (14464645335000).

Almost surely, 2^{261666505504306} is an apocalyptic number.

261666505504306 is a deficient number, since it is larger than the sum of its proper divisors (201202145215694).

261666505504306 is an equidigital number, since it uses as much as digits as its factorization.

261666505504306 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 4285820951 (or 4285820937 counting only the distinct ones).

The product of its (nonzero) digits is 23328000, while the sum is 55.

The spelling of 261666505504306 in words is "two hundred sixty-one trillion, six hundred sixty-six billion, five hundred five million, five hundred four thousand, three hundred six".