66441728 has 20 divisors (see below), whose sum is σ = 132754710. Its totient is φ = 33220608.

The previous prime is 66441719. The next prime is 66441731. The reversal of 66441728 is 82714466.

It can be written as a sum of positive squares in only one way, i.e., 35617024 + 30824704 = 5968^2 + 5552^2 .

It is a junction number, because it is equal to n+sod(n) for n = 66441691 and 66441700.

It is an unprimeable number.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 64373 + ... + 65396.

Almost surely, 2^66441728 is an apocalyptic number.

It is an amenable number.

66441728 is a deficient number, since it is larger than the sum of its proper divisors (66312982).

66441728 is an equidigital number, since it uses as much as digits as its factorization.

66441728 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 129787 (or 129771 counting only the distinct ones).

The product of its digits is 64512, while the sum is 38.

The square root of 66441728 is about 8151.1795465442. The cubic root of 66441728 is about 405.0235783661.

The spelling of 66441728 in words is "sixty-six million, four hundred forty-one thousand, seven hundred twenty-eight".