66644040 has 64 divisors (see below), whose sum is σ = 203342400. Its totient is φ = 17468672.

The previous prime is 66644033. The next prime is 66644057. The reversal of 66644040 is 4044666.

66644040 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.

It is a Harshad number since it is a multiple of its sum of digits (30).

It is a junction number, because it is equal to n+sod(n) for n = 66643989 and 66644007.

It is an unprimeable number.

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 15 ways as a sum of consecutive naturals, for example, 2374 + ... + 11786.

It is an arithmetic number, because the mean of its divisors is an integer number (3177225).

Almost surely, 2^66644040 is an apocalyptic number.

66644040 is a gapful number since it is divisible by the number (60) formed by its first and last digit.

It is an amenable number.

It is a practical number, because each smaller number is the sum of distinct divisors of 66644040, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (101671200).

66644040 is an abundant number, since it is smaller than the sum of its proper divisors (136698360).

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

66644040 is a wasteful number, since it uses less digits than its factorization.

66644040 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 9486 (or 9482 counting only the distinct ones).

The product of its (nonzero) digits is 13824, while the sum is 30.

The square root of 66644040 is about 8163.5800969918. The cubic root of 66644040 is about 405.4342545284.

The spelling of 66644040 in words is "sixty-six million, six hundred forty-four thousand, forty".