2561764975865 has 8 divisors (see below), whose sum is σ = 3074183506368. Its totient is φ = 2049368290480.

The previous prime is 2561764975807. The next prime is 2561764975867. The reversal of 2561764975865 is 5685794671652.

It is a sphenic number, since it is the product of 3 distinct primes.

It is not a de Polignac number, because 2561764975865 - 2²⁸ = 2561496540409 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (2561764975867) 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, 5202167 + ... + 5673276.

It is an arithmetic number, because the mean of its divisors is an integer number (384272938296).

Almost surely, 2^{2561764975865} is an apocalyptic number.

It is an amenable number.

2561764975865 is a deficient number, since it is larger than the sum of its proper divisors (512418530503).

2561764975865 is a wasteful number, since it uses less digits than its factorization.

2561764975865 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 10922559.

The product of its digits is 762048000, while the sum is 71.

The spelling of 2561764975865 in words is "two trillion, five hundred sixty-one billion, seven hundred sixty-four million, nine hundred seventy-five thousand, eight hundred sixty-five".