66866206860 has 384 divisors, whose sum is σ = 219435955200. Its totient is φ = 16885739520.

The previous prime is 66866206819. The next prime is 66866206903. The reversal of 66866206860 is 6860266866.

66866206860 is a `hidden beast` number, since 6 + 6 + 8 + 6 + 620 + 6 + 8 + 6 + 0 = 666.

It is a super-2 number, since 2×66866206860² (a number of 22 digits) contains 22 as substring.

It is a Harshad number since it is a multiple of its sum of digits (54).

It is a junction number, because it is equal to n+sod(n) for n = 66866206797 and 66866206806.

It is an unprimeable number.

It is a polite number, since it can be written in 127 ways as a sum of consecutive naturals, for example, 154425204 + ... + 154425636.

It is an arithmetic number, because the mean of its divisors is an integer number (571447800).

Almost surely, 2^66866206860 is an apocalyptic number.

66866206860 is a gapful number since it is divisible by the number (60) formed by its first and last digit.

It is an amenable number.

It is a practical number, because each smaller number is the sum of distinct divisors of 66866206860, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (109717977600).

66866206860 is an abundant number, since it is smaller than the sum of its proper divisors (152569748340).

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

66866206860 is a wasteful number, since it uses less digits than its factorization.

66866206860 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 678 (or 670 counting only the distinct ones).

The product of its (nonzero) digits is 5971968, while the sum is 54.

The spelling of 66866206860 in words is "sixty-six billion, eight hundred sixty-six million, two hundred six thousand, eight hundred sixty".