261666576287 has 8 divisors (see below), whose sum is σ = 263346342000. Its totient is φ = 259986976704.

The previous prime is 261666576277. The next prime is 261666576293. The reversal of 261666576287 is 782675666162.

It is a happy number.

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 261666576287 - 2¹⁶ = 261666510751 is a prime.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (261666576257) by changing a digit.

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 7 ways as a sum of consecutive naturals, for example, 5354339 + ... + 5402987.

It is an arithmetic number, because the mean of its divisors is an integer number (32918292750).

Almost surely, 2^261666576287 is an apocalyptic number.

261666576287 is a deficient number, since it is larger than the sum of its proper divisors (1679765713).

261666576287 is a wasteful number, since it uses less digits than its factorization.

261666576287 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 83065.

The product of its digits is 60963840, while the sum is 62.

The spelling of 261666576287 in words is "two hundred sixty-one billion, six hundred sixty-six million, five hundred seventy-six thousand, two hundred eighty-seven".