668767760 has 80 divisors (see below), whose sum is σ = 1652238000. Its totient is φ = 250871808.

The previous prime is 668767741. The next prime is 668767789. The reversal of 668767760 is 67767866.

It can be written as a sum of positive squares in 8 ways, for example, as 12588304 + 656179456 = 3548^2 + 25616^2 .

It is a tau number, because it is divible by the number of its divisors (80).

It is an unprimeable number.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 473936 + ... + 475344.

It is an arithmetic number, because the mean of its divisors is an integer number (20652975).

Almost surely, 2^668767760 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 668767760, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (826119000).

668767760 is an abundant number, since it is smaller than the sum of its proper divisors (983470240).

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

668767760 is a wasteful number, since it uses less digits than its factorization.

668767760 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1788 (or 1782 counting only the distinct ones).

The product of its (nonzero) digits is 3556224, while the sum is 53.

The square root of 668767760 is about 25860.5444644926. The cubic root of 668767760 is about 874.4972393406.

It can be divided in two parts, 6687 and 67760, that added together give a palindrome (74447).

The spelling of 668767760 in words is "six hundred sixty-eight million, seven hundred sixty-seven thousand, seven hundred sixty".