66278455616 has 14 divisors (see below), whose sum is σ = 131521310490. Its totient is φ = 33139227776.

The previous prime is 66278455601. The next prime is 66278455651. The reversal of 66278455616 is 61655487266.

It can be written as a sum of positive squares in only one way, i.e., 65597454400 + 681001216 = 256120^2 + 26096^2 .

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 as a sum of consecutive naturals, namely, 517800371 + ... + 517800498.

Almost surely, 2^66278455616 is an apocalyptic number.

It is an amenable number.

66278455616 is a deficient number, since it is larger than the sum of its proper divisors (65242854874).

66278455616 is a wasteful number, since it uses less digits than its factorization.

66278455616 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1035600881 (or 1035600871 counting only the distinct ones).

The product of its digits is 14515200, while the sum is 56.

The spelling of 66278455616 in words is "sixty-six billion, two hundred seventy-eight million, four hundred fifty-five thousand, six hundred sixteen".