66171566 has 16 divisors (see below), whose sum is σ = 104870160. Its totient is φ = 31227840.

The previous prime is 66171559. The next prime is 66171569. The reversal of 66171566 is 66517166.

It is a super-2 number, since 2×66171566² = 8757352293784712, which contains 22 as substring.

It is a Harshad number since it is a multiple of its sum of digits (38).

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (66171569) 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, 7580 + ... + 13776.

It is an arithmetic number, because the mean of its divisors is an integer number (6554385).

Almost surely, 2^66171566 is an apocalyptic number.

66171566 is a deficient number, since it is larger than the sum of its proper divisors (38698594).

66171566 is a wasteful number, since it uses less digits than its factorization.

66171566 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 6499.

The product of its digits is 45360, while the sum is 38.

The square root of 66171566 is about 8134.5907088187. The cubic root of 66171566 is about 404.4738704847.

It can be divided in two parts, 661 and 71566, that added together give a palindrome (72227).

The spelling of 66171566 in words is "sixty-six million, one hundred seventy-one thousand, five hundred sixty-six".