66640378065 has 16 divisors (see below), whose sum is σ = 110064109056. Its totient is φ = 34395033600.

The previous prime is 66640378037. The next prime is 66640378087. The reversal of 66640378065 is 56087304666.

It is not a de Polignac number, because 66640378065 - 2⁸ = 66640377809 is a prime.

It is a super-2 number, since 2×66640378065² (a number of 22 digits) contains 22 as substring.

It is a junction number, because it is equal to n+sod(n) for n = 66640377999 and 66640378017.

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 15 ways as a sum of consecutive naturals, for example, 71655856 + ... + 71656785.

It is an arithmetic number, because the mean of its divisors is an integer number (6879006816).

Almost surely, 2^66640378065 is an apocalyptic number.

It is an amenable number.

66640378065 is a deficient number, since it is larger than the sum of its proper divisors (43423730991).

66640378065 is a wasteful number, since it uses less digits than its factorization.

66640378065 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 143312680.

The product of its (nonzero) digits is 4354560, while the sum is 51.

The spelling of 66640378065 in words is "sixty-six billion, six hundred forty million, three hundred seventy-eight thousand, sixty-five".