66756538671 has 8 divisors (see below), whose sum is σ = 89554784640. Its totient is φ = 44231325912.

The previous prime is 66756538657. The next prime is 66756538721. The reversal of 66756538671 is 17683565766.

It is a sphenic number, since it is the product of 3 distinct primes.

It is not a de Polignac number, because 66756538671 - 2¹⁹ = 66756014383 is a prime.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (66756537671) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 68257731 + ... + 68258708.

It is an arithmetic number, because the mean of its divisors is an integer number (11194348080).

Almost surely, 2^66756538671 is an apocalyptic number.

66756538671 is a deficient number, since it is larger than the sum of its proper divisors (22798245969).

66756538671 is a wasteful number, since it uses less digits than its factorization.

66756538671 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 136516605.

The product of its digits is 38102400, while the sum is 60.

The spelling of 66756538671 in words is "sixty-six billion, seven hundred fifty-six million, five hundred thirty-eight thousand, six hundred seventy-one".