66689540 has 24 divisors (see below), whose sum is σ = 143834712. Its totient is φ = 25954560.

The previous prime is 66689533. The next prime is 66689543. The reversal of 66689540 is 4598666.

66689540 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 41267776 + 25421764 = 6424^2 + 5042^2 .

It is a junction number, because it is equal to n+sod(n) for n = 66689491 and 66689500.

It is not an unprimeable number, because it can be changed into a prime (66689543) 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 7 ways as a sum of consecutive naturals, for example, 44321 + ... + 45800.

It is an arithmetic number, because the mean of its divisors is an integer number (5993113).

Almost surely, 2^66689540 is an apocalyptic number.

It is an amenable number.

66689540 is an abundant number, since it is smaller than the sum of its proper divisors (77145172).

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

66689540 is a wasteful number, since it uses less digits than its factorization.

66689540 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 90167 (or 90165 counting only the distinct ones).

The product of its (nonzero) digits is 311040, while the sum is 44.

The square root of 66689540 is about 8166.3663890374. The cubic root of 66689540 is about 405.5265011469.

The spelling of 66689540 in words is "sixty-six million, six hundred eighty-nine thousand, five hundred forty".