66440140 has 48 divisors (see below), whose sum is σ = 153482112. Its totient is φ = 24005376.

The previous prime is 66440137. The next prime is 66440173. The reversal of 66440140 is 4104466.

It is an unprimeable number.

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, 9502 + ... + 14938.

It is an arithmetic number, because the mean of its divisors is an integer number (3197544).

Almost surely, 2^66440140 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 66440140, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (76741056).

66440140 is an abundant number, since it is smaller than the sum of its proper divisors (87041972).

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

66440140 is a wasteful number, since it uses less digits than its factorization.

66440140 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 5506 (or 5504 counting only the distinct ones).

The product of its (nonzero) digits is 2304, while the sum is 25.

The square root of 66440140 is about 8151.0821367472. The cubic root of 66440140 is about 405.0203515658.

It can be divided in two parts, 664 and 40140, that added together give a palindrome (40804).

The spelling of 66440140 in words is "sixty-six million, four hundred forty thousand, one hundred forty".