666456768 has 224 divisors, whose sum is σ = 2106777600. Its totient is φ = 205949952.

The previous prime is 666456761. The next prime is 666456773. The reversal of 666456768 is 867654666.

It is a super-2 number, since 2×666456768² = 888329247226011648, which contains 22 as substring.

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

It is not an unprimeable number, because it can be changed into a prime (666456761) by changing a digit.

It is a polite number, since it can be written in 31 ways as a sum of consecutive naturals, for example, 1739905 + ... + 1740287.

Almost surely, 2^666456768 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 666456768, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (1053388800).

666456768 is an abundant number, since it is smaller than the sum of its proper divisors (1440320832).

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

666456768 is a wasteful number, since it uses less digits than its factorization.

666456768 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 476 (or 460 counting only the distinct ones).

The product of its digits is 8709120, while the sum is 54.

The square root of 666456768 is about 25815.8239845255. The cubic root of 666456768 is about 873.4887734253.

The spelling of 666456768 in words is "six hundred sixty-six million, four hundred fifty-six thousand, seven hundred sixty-eight".