166665556 has 6 divisors (see below), whose sum is σ = 291664730. Its totient is φ = 83332776.

The previous prime is 166665539. The next prime is 166665557. The reversal of 166665556 is 655566661.

It can be written as a sum of positive squares in only one way, i.e., 165379600 + 1285956 = 12860^2 + 1134^2 .

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (166665557) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 20833191 + ... + 20833198.

Almost surely, 2^166665556 is an apocalyptic number.

It is an amenable number.

166665556 is a deficient number, since it is larger than the sum of its proper divisors (124999174).

166665556 is a wasteful number, since it uses less digits than its factorization.

166665556 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 41666393 (or 41666391 counting only the distinct ones).

The product of its digits is 972000, while the sum is 46.

The square root of 166665556 is about 12909.9014713514. The cubic root of 166665556 is about 550.3199856995.

It can be divided in two parts, 16666 and 5556, that added together give a palindrome (22222).

The spelling of 166665556 in words is "one hundred sixty-six million, six hundred sixty-five thousand, five hundred fifty-six".