66666645 has 40 divisors (see below), whose sum is σ = 120809304. Its totient is φ = 35168256.

The previous prime is 66666643. The next prime is 66666653. The reversal of 66666645 is 54666666.

66666645 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.

It can be written as a sum of positive squares in 4 ways, for example, as 20738916 + 45927729 = 4554^2 + 6777^2 .

It is not a de Polignac number, because 66666645 - 2¹ = 66666643 is a prime.

It is a Harshad number since it is a multiple of its sum of digits (45).

It is a zygodrome in base 3.

It is a self number, because there is not a number n which added to its sum of digits gives 66666645.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (66666643) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 39 ways as a sum of consecutive naturals, for example, 38437 + ... + 40133.

Almost surely, 2^66666645 is an apocalyptic number.

It is an amenable number.

66666645 is a deficient number, since it is larger than the sum of its proper divisors (54142659).

66666645 is a wasteful number, since it uses less digits than its factorization.

66666645 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1811 (or 1802 counting only the distinct ones).

The product of its digits is 933120, while the sum is 45.

The square root of 66666645 is about 8164.9644824702. The cubic root of 66666645 is about 405.4800891112.

The spelling of 66666645 in words is "sixty-six million, six hundred sixty-six thousand, six hundred forty-five".