666065664 has 216 divisors, whose sum is σ = 2149462224. Its totient is φ = 196608000.

The previous prime is 666065629. The next prime is 666065711. The reversal of 666065664 is 466560666.

It is an unprimeable number.

It is a polite number, since it can be written in 23 ways as a sum of consecutive naturals, for example, 1038784 + ... + 1039424.

It is an arithmetic number, because the mean of its divisors is an integer number (9951214).

Almost surely, 2^666065664 is an apocalyptic number.

666065664 is a gapful number since it is divisible by the number (64) 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 666065664, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (1074731112).

666065664 is an abundant number, since it is smaller than the sum of its proper divisors (1483396560).

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

666065664 is a wasteful number, since it uses less digits than its factorization.

666065664 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 715 (or 698 counting only the distinct ones).

The product of its (nonzero) digits is 933120, while the sum is 45.

The square root of 666065664 is about 25808.2479839295. The cubic root of 666065664 is about 873.3178737171.

The spelling of 666065664 in words is "six hundred sixty-six million, sixty-five thousand, six hundred sixty-four".