66408642 has 24 divisors (see below), whose sum is σ = 144696240. Its totient is φ = 22011480.

The previous prime is 66408619. The next prime is 66408649. The reversal of 66408642 is 24680466.

It is a happy number.

66408642 is a `hidden beast` number, since 6 + 6 + 4 + 0 + 8 + 642 = 666.

66408642 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.

It is a junction number, because it is equal to n+sod(n) for n = 66408597 and 66408606.

It is not an unprimeable number, because it can be changed into a prime (66408649) 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 11 ways as a sum of consecutive naturals, for example, 7084 + ... + 13527.

It is an arithmetic number, because the mean of its divisors is an integer number (6029010).

Almost surely, 2^66408642 is an apocalyptic number.

66408642 is an abundant number, since it is smaller than the sum of its proper divisors (78287598).

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

66408642 is a wasteful number, since it uses less digits than its factorization.

66408642 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 20798 (or 20795 counting only the distinct ones).

The product of its (nonzero) digits is 55296, while the sum is 36.

The square root of 66408642 is about 8149.1497716019. The cubic root of 66408642 is about 404.9563373140.

It can be divided in two parts, 664086 and 42, that added together give a triangular number (664128 = T₁₁₅₂).

The spelling of 66408642 in words is "sixty-six million, four hundred eight thousand, six hundred forty-two".