66545 has 4 divisors (see below), whose sum is σ = 79860. Its totient is φ = 53232.

The previous prime is 66541. The next prime is 66553. The reversal of 66545 is 54566.

It is a semiprime because it is the product of two primes, and also an emirpimes, since its reverse is a distinct semiprime: 54566 = 2 ⋅27283.

It can be written as a sum of positive squares in 2 ways, for example, as 8464 + 58081 = 92^2 + 241^2 .

It is a cyclic number.

It is not a de Polignac number, because 66545 - 2² = 66541 is a prime.

It is a plaindrome in base 9.

It is an inconsummate number, since it does not exist a number n which divided by its sum of digits gives 66545.

It is not an unprimeable number, because it can be changed into a prime (66541) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 6650 + ... + 6659.

It is an arithmetic number, because the mean of its divisors is an integer number (19965).

2⁶⁶⁵⁴⁵ is an apocalyptic number.

It is an amenable number.

66545 is a deficient number, since it is larger than the sum of its proper divisors (13315).

66545 is a wasteful number, since it uses less digits than its factorization.

66545 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 13314.

The product of its digits is 3600, while the sum is 26.

The square root of 66545 is about 257.9631756666. The cubic root of 66545 is about 40.5233315749.

The spelling of 66545 in words is "sixty-six thousand, five hundred forty-five".