664717424820 has 24 divisors (see below), whose sum is σ = 1861208789664. Its totient is φ = 177257979936.

The previous prime is 664717424771. The next prime is 664717424827. The reversal of 664717424820 is 28424717466.

It is a happy number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (664717424827) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 5539311814 + ... + 5539311933.

It is an arithmetic number, because the mean of its divisors is an integer number (77550366236).

Almost surely, 2^664717424820 is an apocalyptic number.

664717424820 is a gapful number since it is divisible by the number (60) formed by its first and last digit.

It is an amenable number.

664717424820 is an abundant number, since it is smaller than the sum of its proper divisors (1196491364844).

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

664717424820 is a wasteful number, since it uses less digits than its factorization.

664717424820 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 11078623759 (or 11078623757 counting only the distinct ones).

The product of its (nonzero) digits is 3612672, while the sum is 51.

The spelling of 664717424820 in words is "six hundred sixty-four billion, seven hundred seventeen million, four hundred twenty-four thousand, eight hundred twenty".