66446720 has 64 divisors (see below), whose sum is σ = 162302400. Its totient is φ = 26013184.

The previous prime is 66446713. The next prime is 66446741. The reversal of 66446720 is 2764466.

It is a happy number.

It is a tau number, because it is divible by the number of its divisors (64).

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 1413737 + ... + 1413783.

It is an arithmetic number, because the mean of its divisors is an integer number (2535975).

Almost surely, 2^66446720 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 66446720, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (81151200).

66446720 is an abundant number, since it is smaller than the sum of its proper divisors (95855680).

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

66446720 is an frugal number, since it uses more digits than its factorization.

66446720 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 160 (or 54 counting only the distinct ones).

The product of its (nonzero) digits is 48384, while the sum is 35.

The square root of 66446720 is about 8151.4857541432. The cubic root of 66446720 is about 405.0337217260.

The spelling of 66446720 in words is "sixty-six million, four hundred forty-six thousand, seven hundred twenty".