66171678061 has 4 divisors (see below), whose sum is σ = 66208218624. Its totient is φ = 66135137500.

The previous prime is 66171678049. The next prime is 66171678107. The reversal of 66171678061 is 16087617166.

It is a semiprime because it is the product of two primes, and also a Blum integer, because the two primes are equal to 3 mod 4.

It is a cyclic number.

It is not a de Polignac number, because 66171678061 - 2²⁹ = 65634807149 is a prime.

It is a Smith number, since the sum of its digits (49) coincides with the sum of the digits of its prime factors. Since it is squarefree, it is also a hoax number.

It is a Duffinian number.

It is a junction number, because it is equal to n+sod(n) for n = 66171677996 and 66171678014.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (66171678011) 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, 18267565 + ... + 18271186.

It is an arithmetic number, because the mean of its divisors is an integer number (16552054656).

Almost surely, 2^66171678061 is an apocalyptic number.

It is an amenable number.

66171678061 is a deficient number, since it is larger than the sum of its proper divisors (36540563).

66171678061 is a wasteful number, since it uses less digits than its factorization.

66171678061 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 36540562.

The product of its (nonzero) digits is 508032, while the sum is 49.

The spelling of 66171678061 in words is "sixty-six billion, one hundred seventy-one million, six hundred seventy-eight thousand, sixty-one".