66857255361 has 64 divisors (see below), whose sum is σ = 108433561600. Its totient is φ = 40463489088.

The previous prime is 66857255327. The next prime is 66857255369. The reversal of 66857255361 is 16355275866.

It is a happy number.

66857255361 is a `hidden beast` number, since 6 + 6 + 8 + 572 + 5 + 5 + 3 + 61 = 666.

It is not a de Polignac number, because 66857255361 - 2¹¹ = 66857253313 is a prime.

It is a Curzon number.

It is a junction number, because it is equal to n+sod(n) for n = 66857255298 and 66857255307.

It is not an unprimeable number, because it can be changed into a prime (66857255369) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 63 ways as a sum of consecutive naturals, for example, 17377140 + ... + 17380986.

It is an arithmetic number, because the mean of its divisors is an integer number (1694274400).

Almost surely, 2^66857255361 is an apocalyptic number.

It is an amenable number.

66857255361 is a deficient number, since it is larger than the sum of its proper divisors (41576306239).

66857255361 is a wasteful number, since it uses less digits than its factorization.

66857255361 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 4675 (or 4669 counting only the distinct ones).

The product of its digits is 9072000, while the sum is 54.

The spelling of 66857255361 in words is "sixty-six billion, eight hundred fifty-seven million, two hundred fifty-five thousand, three hundred sixty-one".