166666644 has 18 divisors (see below), whose sum is σ = 421296330. Its totient is φ = 55555536.

The previous prime is 166666639. The next prime is 166666649. The reversal of 166666644 is 446666661.

166666644 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.

It is an interprime number because it is at equal distance from previous prime (166666639) and next prime (166666649).

It can be written as a sum of positive squares in only one way, i.e., 162256644 + 4410000 = 12738^2 + 2100^2 .

It is a tau number, because it is divible by the number of its divisors (18).

It is a nude number because it is divisible by every one of its digits.

It is a self number, because there is not a number n which added to its sum of digits gives 166666644.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (166666649) by changing a digit.

It is a polite number, since it can be written in 5 ways as a sum of consecutive naturals, for example, 2314779 + ... + 2314850.

Almost surely, 2^166666644 is an apocalyptic number.

It is an amenable number.

166666644 is an abundant number, since it is smaller than the sum of its proper divisors (254629686).

It is a pseudoperfect number, because it is the sum of a subset of its proper divisors.

166666644 is a wasteful number, since it uses less digits than its factorization.

166666644 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 4629639 (or 4629634 counting only the distinct ones).

The product of its digits is 746496, while the sum is 45.

The square root of 166666644 is about 12909.9436094818. The cubic root of 166666644 is about 550.3211832012.

The spelling of 166666644 in words is "one hundred sixty-six million, six hundred sixty-six thousand, six hundred forty-four".