66720144 has 20 divisors (see below), whose sum is σ = 172360496. Its totient is φ = 22240032.

The previous prime is 66720109. The next prime is 66720149. The reversal of 66720144 is 44102766.

It is not an unprimeable number, because it can be changed into a prime (66720149) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 694954 + ... + 695049.

Almost surely, 2^66720144 is an apocalyptic number.

It is an amenable number.

66720144 is an abundant number, since it is smaller than the sum of its proper divisors (105640352).

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

66720144 is a wasteful number, since it uses less digits than its factorization.

66720144 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1390014 (or 1390008 counting only the distinct ones).

The product of its (nonzero) digits is 8064, while the sum is 30.

The square root of 66720144 is about 8168.2399572980. The cubic root of 66720144 is about 405.5885240423.

The spelling of 66720144 in words is "sixty-six million, seven hundred twenty thousand, one hundred forty-four".