66444240 has 80 divisors (see below), whose sum is σ = 214950528. Its totient is φ = 16946688.

The previous prime is 66444227. The next prime is 66444271. The reversal of 66444240 is 4244466.

It is a tau number, because it is divible by the number of its divisors (80).

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 = 66444198 and 66444207.

It is a congruent number.

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, 499 + ... + 11538.

Almost surely, 2^66444240 is an apocalyptic number.

66444240 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 66444240, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (107475264).

66444240 is an abundant number, since it is smaller than the sum of its proper divisors (148506288).

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

66444240 is a wasteful number, since it uses less digits than its factorization.

66444240 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 12076 (or 12070 counting only the distinct ones).

The product of its (nonzero) digits is 18432, while the sum is 30.

The square root of 66444240 is about 8151.3336332161. Note that the first 3 decimals coincide. The cubic root of 66444240 is about 405.0286826203.

The spelling of 66444240 in words is "sixty-six million, four hundred forty-four thousand, two hundred forty".