666415680 has 336 divisors, whose sum is σ = 2546274816. Its totient is φ = 147087360.

The previous prime is 666415627. The next prime is 666415721. The reversal of 666415680 is 86514666.

It is a tau number, because it is divible by the number of its divisors (336).

It is a Harshad number since it is a multiple of its sum of digits (42).

It is an unprimeable number.

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 47 ways as a sum of consecutive naturals, for example, 1458012 + ... + 1458468.

Almost surely, 2^666415680 is an apocalyptic number.

666415680 is a gapful number since it is divisible by the number (60) 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 666415680, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (1273137408).

666415680 is an abundant number, since it is smaller than the sum of its proper divisors (1879859136).

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

666415680 is a wasteful number, since it uses less digits than its factorization.

666415680 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 522 (or 505 counting only the distinct ones).

The product of its (nonzero) digits is 207360, while the sum is 42.

The square root of 666415680 is about 25815.0281812746. The cubic root of 666415680 is about 873.4708224513.

The spelling of 666415680 in words is "six hundred sixty-six million, four hundred fifteen thousand, six hundred eighty".