66513728 has 28 divisors (see below), whose sum is σ = 134485380. Its totient is φ = 32627712.

The previous prime is 66513719. The next prime is 66513739. The reversal of 66513728 is 82731566.

It can be written as a sum of positive squares in 2 ways, for example, as 60715264 + 5798464 = 7792^2 + 2408^2 .

It is a junction number, because it is equal to n+sod(n) for n = 66513691 and 66513700.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 6413 + ... + 13196.

Almost surely, 2^66513728 is an apocalyptic number.

It is an amenable number.

66513728 is an abundant number, since it is smaller than the sum of its proper divisors (67971652).

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

66513728 is a wasteful number, since it uses less digits than its factorization.

66513728 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 19674 (or 19664 counting only the distinct ones).

The product of its digits is 60480, while the sum is 38.

The square root of 66513728 is about 8155.5948893995. The cubic root of 66513728 is about 405.1698276741.

The spelling of 66513728 in words is "sixty-six million, five hundred thirteen thousand, seven hundred twenty-eight".