261556160260405 has 16 divisors (see below), whose sum is σ = 313980095784960. Its totient is φ = 209169798308352.

The previous prime is 261556160260399. The next prime is 261556160260433. The reversal of 261556160260405 is 504062061655162.

It is a cyclic number.

It is not a de Polignac number, because 261556160260405 - 2²³ = 261556151871797 is a prime.

It is a congruent number.

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (23) of ones.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 377904901 + ... + 378596389.

It is an arithmetic number, because the mean of its divisors is an integer number (19623755986560).

Almost surely, 2^{261556160260405} is an apocalyptic number.

It is an amenable number.

261556160260405 is a deficient number, since it is larger than the sum of its proper divisors (52423935524555).

261556160260405 is a wasteful number, since it uses less digits than its factorization.

261556160260405 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 718548.

The product of its (nonzero) digits is 2592000, while the sum is 49.

The spelling of 261556160260405 in words is "two hundred sixty-one trillion, five hundred fifty-six billion, one hundred sixty million, two hundred sixty thousand, four hundred five".