261564210617064 has 64 divisors (see below), whose sum is σ = 655571385541440. Its totient is φ = 86966631544320.

The previous prime is 261564210617011. The next prime is 261564210617069. The reversal of 261564210617064 is 460716012465162.

It is a junction number, because it is equal to n+sod(n) for n = 261564210616998 and 261564210617016.

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 15 ways as a sum of consecutive naturals, for example, 500463799 + ... + 500986169.

It is an arithmetic number, because the mean of its divisors is an integer number (10243302899085).

Almost surely, 2^{261564210617064} is an apocalyptic number.

261564210617064 is a gapful number since it is divisible by the number (24) formed by its first and last digit.

It is an amenable number.

261564210617064 is an abundant number, since it is smaller than the sum of its proper divisors (394007174924376).

It is a pseudoperfect number, because it is the sum of a subset of its proper divisors.

261564210617064 is a wasteful number, since it uses less digits than its factorization.

261564210617064 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 575330 (or 575326 counting only the distinct ones).

The product of its (nonzero) digits is 2903040, while the sum is 51.

The spelling of 261564210617064 in words is "two hundred sixty-one trillion, five hundred sixty-four billion, two hundred ten million, six hundred seventeen thousand, sixty-four".