666520198857240 has 512 divisors, whose sum is σ = 2541072560947200. Its totient is φ = 136055185643520.

The previous prime is 666520198857197. The next prime is 666520198857257. The reversal of 666520198857240 is 42758891025666.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 127 ways as a sum of consecutive naturals, for example, 1258691169 + ... + 1259220591.

It is an arithmetic number, because the mean of its divisors is an integer number (4963032345600).

Almost surely, 2^{666520198857240} is an apocalyptic number.

666520198857240 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 666520198857240, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (1270536280473600).

666520198857240 is an abundant number, since it is smaller than the sum of its proper divisors (1874552362089960).

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

666520198857240 is a wasteful number, since it uses less digits than its factorization.

666520198857240 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 533207 (or 533203 counting only the distinct ones).

The product of its (nonzero) digits is 348364800, while the sum is 69.

The spelling of 666520198857240 in words is "six hundred sixty-six trillion, five hundred twenty billion, one hundred ninety-eight million, eight hundred fifty-seven thousand, two hundred forty".