66541463617 has 4 divisors (see below), whose sum is σ = 66543007060. Its totient is φ = 66539920176.

The previous prime is 66541463609. The next prime is 66541463647. The reversal of 66541463617 is 71636414566.

66541463617 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.

It is a semiprime because it is the product of two primes, and also an emirpimes, since its reverse is a distinct semiprime: 71636414566 = 2 ⋅35818207283.

It can be written as a sum of positive squares in 2 ways, for example, as 47297115441 + 19244348176 = 217479^2 + 138724^2 .

It is a cyclic number.

It is not a de Polignac number, because 66541463617 - 2³ = 66541463609 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (66541463647) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 705138 + ... + 793915.

It is an arithmetic number, because the mean of its divisors is an integer number (16635751765).

Almost surely, 2^66541463617 is an apocalyptic number.

It is an amenable number.

66541463617 is a deficient number, since it is larger than the sum of its proper divisors (1543443).

66541463617 is a wasteful number, since it uses less digits than its factorization.

66541463617 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1543442.

The product of its digits is 2177280, while the sum is 49.

The spelling of 66541463617 in words is "sixty-six billion, five hundred forty-one million, four hundred sixty-three thousand, six hundred seventeen".