261564210617065 has 8 divisors (see below), whose sum is σ = 313906644305280. Its totient is φ = 209231640783792.

The previous prime is 261564210617011. The next prime is 261564210617069. The reversal of 261564210617065 is 560716012465162.

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 261564210617065 - 2³⁹ = 261014454803177 is a prime.

It is not an unprimeable number, because it can be changed into a prime (261564210617069) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 2465905395 + ... + 2466011464.

It is an arithmetic number, because the mean of its divisors is an integer number (39238330538160).

Almost surely, 2^{261564210617065} is an apocalyptic number.

It is an amenable number.

261564210617065 is a deficient number, since it is larger than the sum of its proper divisors (52342433688215).

261564210617065 is a wasteful number, since it uses less digits than its factorization.

261564210617065 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 4931927471.

The product of its (nonzero) digits is 3628800, while the sum is 52.

The spelling of 261564210617065 in words is "two hundred sixty-one trillion, five hundred sixty-four billion, two hundred ten million, six hundred seventeen thousand, sixty-five".