6666406656 has 576 divisors, whose sum is σ = 23998980096. Its totient is φ = 1592524800.

The previous prime is 6666406651. The next prime is 6666406667. The reversal of 6666406656 is 6566046666.

It is a happy number.

It is a super-2 number, since 2×6666406656² = 88881955406322204672, which contains 22 as substring.

It is a Harshad number since it is a multiple of its sum of digits (51).

It is a junction number, because it is equal to n+sod(n) for n = 6666406599 and 6666406608.

It is not an unprimeable number, because it can be changed into a prime (6666406651) 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, 36830886 + ... + 36831066.

It is an arithmetic number, because the mean of its divisors is an integer number (41664896).

Almost surely, 2^6666406656 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 6666406656, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (11999490048).

6666406656 is an abundant number, since it is smaller than the sum of its proper divisors (17332573440).

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

6666406656 is a wasteful number, since it uses less digits than its factorization.

6666406656 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 268 (or 254 counting only the distinct ones).

The product of its (nonzero) digits is 5598720, while the sum is 51.

The square root of 6666406656 is about 81648.0658435948. The cubic root of 6666406656 is about 1882.0475895034.

The spelling of 6666406656 in words is "six billion, six hundred sixty-six million, four hundred six thousand, six hundred fifty-six".