66171261 has 32 divisors (see below), whose sum is σ = 97469568. Its totient is φ = 39686400.

The previous prime is 66171257. The next prime is 66171271. The reversal of 66171261 is 16217166.

It is not a de Polignac number, because 66171261 - 2² = 66171257 is a prime.

It is a Smith number, since the sum of its digits (30) coincides with the sum of the digits of its prime factors. Since it is squarefree, it is also a hoax number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (66171221) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written in 31 ways as a sum of consecutive naturals, for example, 421395 + ... + 421551.

It is an arithmetic number, because the mean of its divisors is an integer number (3045924).

Almost surely, 2^66171261 is an apocalyptic number.

It is an amenable number.

66171261 is a deficient number, since it is larger than the sum of its proper divisors (31298307).

66171261 is a wasteful number, since it uses less digits than its factorization.

66171261 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 381.

The product of its digits is 3024, while the sum is 30.

The square root of 66171261 is about 8134.5719616953. The cubic root of 66171261 is about 404.4732490459.

The spelling of 66171261 in words is "sixty-six million, one hundred seventy-one thousand, two hundred sixty-one".