66865655656866 has 64 divisors (see below), whose sum is σ = 152371160847360. Its totient is φ = 19380542304960.

The previous prime is 66865655656837. The next prime is 66865655656889.

66865655656866 is nontrivially palindromic in base 10.

It is a super-2 number, since 2×66865655656866² (a number of 28 digits) contains 22 as substring.

It is an unprimeable number.

It is a polite number, since it can be written in 31 ways as a sum of consecutive naturals, for example, 231902646 + ... + 232190801.

It is an arithmetic number, because the mean of its divisors is an integer number (2380799388240).

Almost surely, 2^{66865655656866} is an apocalyptic number.

66865655656866 is a gapful number since it is divisible by the number (66) formed by its first and last digit.

66865655656866 is an abundant number, since it is smaller than the sum of its proper divisors (85505505190494).

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

66865655656866 is a wasteful number, since it uses less digits than its factorization.

66865655656866 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 464093559.

The product of its digits is 67184640000, while the sum is 84.

The spelling of 66865655656866 in words is "sixty-six trillion, eight hundred sixty-five billion, six hundred fifty-five million, six hundred fifty-six thousand, eight hundred sixty-six".