66562217856 has 768 divisors, whose sum is σ = 224550144000. Its totient is φ = 19526842368.

The previous prime is 66562217851. The next prime is 66562217861. The reversal of 66562217856 is 65871226566.

66562217856 is a `hidden beast` number, since 6 + 6 + 5 + 622 + 1 + 7 + 8 + 5 + 6 = 666.

It is an interprime number because it is at equal distance from previous prime (66562217851) and next prime (66562217861).

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

Its product of digits (7257600) is a multiple of the sum of its prime divisors (189).

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (66562217851) by changing a digit.

It is a polite number, since it can be written in 95 ways as a sum of consecutive naturals, for example, 801954391 + ... + 801954473.

It is an arithmetic number, because the mean of its divisors is an integer number (292383000).

Almost surely, 2^66562217856 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 66562217856, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (112275072000).

66562217856 is an abundant number, since it is smaller than the sum of its proper divisors (157987926144).

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

66562217856 is a wasteful number, since it uses less digits than its factorization.

66562217856 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 213 (or 189 counting only the distinct ones).

The product of its digits is 7257600, while the sum is 54.

The spelling of 66562217856 in words is "sixty-six billion, five hundred sixty-two million, two hundred seventeen thousand, eight hundred fifty-six".