66404663621664 has 48 divisors (see below), whose sum is σ = 174312758571840. Its totient is φ = 22134822278400.

The previous prime is 66404663621629. The next prime is 66404663621669. The reversal of 66404663621664 is 46612636640466.

It is a tau number, because it is divible by the number of its divisors (48).

It is a junction number, because it is equal to n+sod(n) for n = 66404663621598 and 66404663621607.

It is not an unprimeable number, because it can be changed into a prime (66404663621669) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (19) of ones.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 40080114 + ... + 41704014.

It is an arithmetic number, because the mean of its divisors is an integer number (3631515803580).

Almost surely, 2^{66404663621664} is an apocalyptic number.

It is an amenable number.

66404663621664 is an abundant number, since it is smaller than the sum of its proper divisors (107908094950176).

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

66404663621664 is a wasteful number, since it uses less digits than its factorization.

66404663621664 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 2049873 (or 2049865 counting only the distinct ones).

The product of its (nonzero) digits is 107495424, while the sum is 60.

The spelling of 66404663621664 in words is "sixty-six trillion, four hundred four billion, six hundred sixty-three million, six hundred twenty-one thousand, six hundred sixty-four".