66645 has 12 divisors (see below), whose sum is σ = 115596. Its totient is φ = 35520.

The previous prime is 66643. The next prime is 66653. The reversal of 66645 is 54666.

It can be written as a sum of positive squares in 2 ways, for example, as 26244 + 40401 = 162^2 + 201^2 .

It is not a de Polignac number, because 66645 - 2¹ = 66643 is a prime.

It is a plaindrome in base 13.

It is a congruent number.

It is an inconsummate number, since it does not exist a number n which divided by its sum of digits gives 66645.

It is not an unprimeable number, because it can be changed into a prime (66643) by changing a digit.

It is a polite number, since it can be written in 11 ways as a sum of consecutive naturals, for example, 696 + ... + 785.

It is an arithmetic number, because the mean of its divisors is an integer number (9633).

2⁶⁶⁶⁴⁵ is an apocalyptic number.

It is an amenable number.

66645 is a deficient number, since it is larger than the sum of its proper divisors (48951).

66645 is a wasteful number, since it uses less digits than its factorization.

66645 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1492 (or 1489 counting only the distinct ones).

The product of its digits is 4320, while the sum is 27.

The square root of 66645 is about 258.1569290180. The cubic root of 66645 is about 40.5436201264.

The spelling of 66645 in words is "sixty-six thousand, six hundred forty-five".