668240549798640 has 640 divisors, whose sum is σ = 2684452190730240. Its totient is φ = 133537552072704.

The previous prime is 668240549798561. The next prime is 668240549798693. The reversal of 668240549798640 is 46897945042866.

It is a Harshad number since it is a multiple of its sum of digits (78).

It is a congruent number.

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (23) of ones.

It is a polite number, since it can be written in 127 ways as a sum of consecutive naturals, for example, 1683294252 + ... + 1683691188.

It is an arithmetic number, because the mean of its divisors is an integer number (4194456548016).

Almost surely, 2^{668240549798640} is an apocalyptic number.

668240549798640 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 668240549798640, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (1342226095365120).

668240549798640 is an abundant number, since it is smaller than the sum of its proper divisors (2016211640931600).

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

668240549798640 is a wasteful number, since it uses less digits than its factorization.

668240549798640 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 401049 (or 401043 counting only the distinct ones).

The product of its (nonzero) digits is 5016453120, while the sum is 78.

The spelling of 668240549798640 in words is "six hundred sixty-eight trillion, two hundred forty billion, five hundred forty-nine million, seven hundred ninety-eight thousand, six hundred forty".