66396405625 has 45 divisors (see below), whose sum is σ = 91294706811. Its totient is φ = 48236760000.

The previous prime is 66396405601. The next prime is 66396405679. The reversal of 66396405625 is 52650469366.

The square root of 66396405625 is 257675.

It is a perfect power (a square), and thus also a powerful number.

It can be written as a sum of positive squares in 7 ways, for example, as 66215126329 + 181279296 = 257323^2 + 13464^2 .

It is a de Polignac number, because none of the positive numbers 2^k-66396405625 is a prime.

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (23) of ones.

It is a polite number, since it can be written in 44 ways as a sum of consecutive naturals, for example, 70860157 + ... + 70861093.

Almost surely, 2^66396405625 is an apocalyptic number.

66396405625 is the 257675-th square number.

66396405625 is the 128838-th centered octagonal number.

It is an amenable number.

66396405625 is a deficient number, since it is larger than the sum of its proper divisors (24898301186).

66396405625 is an frugal number, since it uses more digits than its factorization.

66396405625 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1916 (or 953 counting only the distinct ones).

The product of its (nonzero) digits is 6998400, while the sum is 52.

The spelling of 66396405625 in words is "sixty-six billion, three hundred ninety-six million, four hundred five thousand, six hundred twenty-five".