266761772488656 has 960 divisors, whose sum is σ = 832300607923200. Its totient is φ = 81732138808320.

The previous prime is 266761772488639. The next prime is 266761772488697. The reversal of 266761772488656 is 656884277167662.

266761772488656 is a `hidden beast` number, since 2 + 6 + 6 + 7 + 6 + 1 + 7 + 72 + 488 + 65 + 6 = 666.

It is a super-2 number, since 2×266761772488656² (a number of 30 digits) contains 22 as substring.

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 191 ways as a sum of consecutive naturals, for example, 86978078835 + ... + 86978081901.

It is an arithmetic number, because the mean of its divisors is an integer number (866979799920).

Almost surely, 2^{266761772488656} is an apocalyptic number.

It is an amenable number.

It is a practical number, because each smaller number is the sum of distinct divisors of 266761772488656, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (416150303961600).

266761772488656 is an abundant number, since it is smaller than the sum of its proper divisors (565538835434544).

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

266761772488656 is a wasteful number, since it uses less digits than its factorization.

266761772488656 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 3325 (or 3282 counting only the distinct ones).

The product of its digits is 13655900160, while the sum is 81.

The spelling of 266761772488656 in words is "two hundred sixty-six trillion, seven hundred sixty-one billion, seven hundred seventy-two million, four hundred eighty-eight thousand, six hundred fifty-six".