65694947878564 has 81 divisors (see below), whose sum is σ = 119310734593953. Its totient is φ = 31650905168064.

The previous prime is 65694947878543. The next prime is 65694947878619. The reversal of 65694947878564 is 46587874949656.

The square root of 65694947878564 is 8105242.

It is a perfect power (a square), and thus also a powerful number.

65694947878564 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.

It can be written as a sum of positive squares in only one way, i.e., 33742970676900 + 31951977201664 = 5808870^2 + 5652608^2 .

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (23) of ones.

It is a polite number, since it can be written in 26 ways as a sum of consecutive naturals, for example, 55067013552 + ... + 55067014744.

Almost surely, 2^{65694947878564} is an apocalyptic number.

65694947878564 is the 8105242-nd square number.

It is an amenable number.

65694947878564 is a deficient number, since it is larger than the sum of its proper divisors (53615786715389).

65694947878564 is an frugal number, since it uses more digits than its factorization.

65694947878564 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 2634 (or 1317 counting only the distinct ones).

The product of its digits is 87787929600, while the sum is 88.

The spelling of 65694947878564 in words is "sixty-five trillion, six hundred ninety-four billion, nine hundred forty-seven million, eight hundred seventy-eight thousand, five hundred sixty-four".