66545573 has 4 divisors (see below), whose sum is σ = 68344140. Its totient is φ = 64747008.

The previous prime is 66545551. The next prime is 66545579. The reversal of 66545573 is 37554566.

It is a semiprime because it is the product of two primes.

It can be written as a sum of positive squares in 2 ways, for example, as 39526369 + 27019204 = 6287^2 + 5198^2 .

It is a cyclic number.

It is not a de Polignac number, because 66545573 - 2¹⁰ = 66544549 is a prime.

It is a Duffinian number.

It is a self number, because there is not a number n which added to its sum of digits gives 66545573.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (66545579) 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, 899228 + ... + 899301.

It is an arithmetic number, because the mean of its divisors is an integer number (17086035).

Almost surely, 2^66545573 is an apocalyptic number.

It is an amenable number.

66545573 is a deficient number, since it is larger than the sum of its proper divisors (1798567).

66545573 is a wasteful number, since it uses less digits than its factorization.

66545573 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1798566.

The product of its digits is 378000, while the sum is 41.

The square root of 66545573 is about 8157.5469964935. The cubic root of 66545573 is about 405.2344788620.

The spelling of 66545573 in words is "sixty-six million, five hundred forty-five thousand, five hundred seventy-three".