66440440 has 64 divisors (see below), whose sum is σ = 168376320. Its totient is φ = 23376000.

The previous prime is 66440401. The next prime is 66440447. The reversal of 66440440 is 4404466.

It is a junction number, because it is equal to n+sod(n) for n = 66440399 and 66440408.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (66440447) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 11205 + ... + 16075.

It is an arithmetic number, because the mean of its divisors is an integer number (2630880).

Almost surely, 2^66440440 is an apocalyptic number.

It is an amenable number.

It is a practical number, because each smaller number is the sum of distinct divisors of 66440440, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (84188160).

66440440 is an abundant number, since it is smaller than the sum of its proper divisors (101935880).

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

66440440 is a wasteful number, since it uses less digits than its factorization.

66440440 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 4924 (or 4920 counting only the distinct ones).

The product of its (nonzero) digits is 9216, while the sum is 28.

The square root of 66440440 is about 8151.1005391910. The cubic root of 66440440 is about 405.0209611668.

It can be divided in two parts, 6 and 6440440, that added together give a palindrome (6440446).

The spelling of 66440440 in words is "sixty-six million, four hundred forty thousand, four hundred forty".