66781540 has 24 divisors (see below), whose sum is σ = 160276032. Its totient is φ = 22896480.

The previous prime is 66781487. The next prime is 66781541. The reversal of 66781540 is 4518766.

66781540 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.

It is a self number, because there is not a number n which added to its sum of digits gives 66781540.

It is not an unprimeable number, because it can be changed into a prime (66781541) 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, 238366 + ... + 238645.

It is an arithmetic number, because the mean of its divisors is an integer number (6678168).

Almost surely, 2^66781540 is an apocalyptic number.

It is an amenable number.

66781540 is an abundant number, since it is smaller than the sum of its proper divisors (93494492).

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

66781540 is a wasteful number, since it uses less digits than its factorization.

66781540 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 477027 (or 477025 counting only the distinct ones).

The product of its (nonzero) digits is 40320, while the sum is 37.

The square root of 66781540 is about 8171.9973078801. The cubic root of 66781540 is about 405.7128936718.

The spelling of 66781540 in words is "sixty-six million, seven hundred eighty-one thousand, five hundred forty".