668511404820 has 288 divisors, whose sum is σ = 2529833779200. Its totient is φ = 144760224384.

The previous prime is 668511404809. The next prime is 668511404857. The reversal of 668511404820 is 28404115866.

It is a happy number.

It is a super-3 number, since 3×668511404820³ (a number of 36 digits) contains 333 as substring.

It is a Harshad number since it is a multiple of its sum of digits (45).

It is a congruent number.

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 95 ways as a sum of consecutive naturals, for example, 129261 + ... + 1163499.

Almost surely, 2^668511404820 is an apocalyptic number.

668511404820 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 668511404820, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (1264916889600).

668511404820 is an abundant number, since it is smaller than the sum of its proper divisors (1861322374380).

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

668511404820 is a wasteful number, since it uses less digits than its factorization.

668511404820 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1034289 (or 1034275 counting only the distinct ones).

The product of its (nonzero) digits is 368640, while the sum is 45.

The spelling of 668511404820 in words is "six hundred sixty-eight billion, five hundred eleven million, four hundred four thousand, eight hundred twenty".