66506637543 has 4 divisors (see below), whose sum is σ = 88675516728. Its totient is φ = 44337758360.

The previous prime is 66506637529. The next prime is 66506637559. The reversal of 66506637543 is 34573660566.

It is a semiprime because it is the product of two primes.

It is a cyclic number.

It is not a de Polignac number, because 66506637543 - 2⁹ = 66506637031 is a prime.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (66506637443) 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, 11084439588 + ... + 11084439593.

It is an arithmetic number, because the mean of its divisors is an integer number (22168879182).

Almost surely, 2^66506637543 is an apocalyptic number.

66506637543 is a deficient number, since it is larger than the sum of its proper divisors (22168879185).

66506637543 is a wasteful number, since it uses less digits than its factorization.

66506637543 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 22168879184.

The product of its (nonzero) digits is 8164800, while the sum is 51.

The spelling of 66506637543 in words is "sixty-six billion, five hundred six million, six hundred thirty-seven thousand, five hundred forty-three".