66389472 has 72 divisors (see below), whose sum is σ = 191940840. Its totient is φ = 21761280.

The previous prime is 66389447. The next prime is 66389501. The reversal of 66389472 is 27498366.

66389472 is a `hidden beast` number, since 6 + 638 + 9 + 4 + 7 + 2 = 666.

66389472 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.

It is a tau number, because it is divible by the number of its divisors (72).

It is a congruent number.

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 11 ways as a sum of consecutive naturals, for example, 15679 + ... + 19457.

It is an arithmetic number, because the mean of its divisors is an integer number (2665845).

Almost surely, 2^66389472 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 66389472, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (95970420).

66389472 is an abundant number, since it is smaller than the sum of its proper divisors (125551368).

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

66389472 is a wasteful number, since it uses less digits than its factorization.

66389472 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 3856 (or 3845 counting only the distinct ones).

The product of its digits is 435456, while the sum is 45.

The square root of 66389472 is about 8147.9734903840. The cubic root of 66389472 is about 404.9173676867.

It can be divided in two parts, 6638 and 9472, that added together give a triangular number (16110 = T₁₇₉).

The spelling of 66389472 in words is "sixty-six million, three hundred eighty-nine thousand, four hundred seventy-two".