66416289728256 has 720 divisors, whose sum is σ = 231742825431040. Its totient is φ = 18735646187520.

The previous prime is 66416289728231. The next prime is 66416289728273. The reversal of 66416289728256 is 65282798261466.

66416289728256 is a `hidden beast` number, since 6 + 6 + 4 + 16 + 289 + 7 + 282 + 56 = 666.

It is a super-2 number, since 2×66416289728256² (a number of 28 digits) contains 22 as substring.

It is a Harshad number since it is a multiple of its sum of digits (72).

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 79 ways as a sum of consecutive naturals, for example, 158566401 + ... + 158984703.

Almost surely, 2^{66416289728256} 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 66416289728256, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (115871412715520).

66416289728256 is an abundant number, since it is smaller than the sum of its proper divisors (165326535702784).

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

66416289728256 is a wasteful number, since it uses less digits than its factorization.

66416289728256 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 418394 (or 418371 counting only the distinct ones).

The product of its digits is 836075520, while the sum is 72.

The spelling of 66416289728256 in words is "sixty-six trillion, four hundred sixteen billion, two hundred eighty-nine million, seven hundred twenty-eight thousand, two hundred fifty-six".