666688164480 has 640 divisors, whose sum is σ = 2633403160080. Its totient is φ = 159666536448.

The previous prime is 666688164427. The next prime is 666688164547. The reversal of 666688164480 is 84461886666.

It can be written as a sum of positive squares in 8 ways, for example, as 366392932416 + 300295232064 = 605304^2 + 547992^2 .

It is a tau number, because it is divible by the number of its divisors (640).

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written in 79 ways as a sum of consecutive naturals, for example, 24921672 + ... + 24948408.

Almost surely, 2^666688164480 is an apocalyptic number.

666688164480 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 666688164480, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (1316701580040).

666688164480 is an abundant number, since it is smaller than the sum of its proper divisors (1966714995600).

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

666688164480 is a wasteful number, since it uses less digits than its factorization.

666688164480 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 26818 (or 26797 counting only the distinct ones).

The product of its (nonzero) digits is 63700992, while the sum is 63.

The spelling of 666688164480 in words is "six hundred sixty-six billion, six hundred eighty-eight million, one hundred sixty-four thousand, four hundred eighty".