66404891980 has 48 divisors (see below), whose sum is σ = 159663280896. Its totient is φ = 22725743040.

The previous prime is 66404891957. The next prime is 66404892031. The reversal of 66404891980 is 8919840466.

It is an unprimeable number.

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 15 ways as a sum of consecutive naturals, for example, 356986 + ... + 510145.

It is an arithmetic number, because the mean of its divisors is an integer number (3326318352).

Almost surely, 2^66404891980 is an apocalyptic number.

It is an amenable number.

66404891980 is an abundant number, since it is smaller than the sum of its proper divisors (93258388916).

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

66404891980 is a wasteful number, since it uses less digits than its factorization.

66404891980 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 867694 (or 867692 counting only the distinct ones).

The product of its (nonzero) digits is 2985984, while the sum is 55.

The spelling of 66404891980 in words is "sixty-six billion, four hundred four million, eight hundred ninety-one thousand, nine hundred eighty".