66444857361 has 21 divisors (see below), whose sum is σ = 99632149401. Its totient is φ = 44291931732.

The previous prime is 66444857273. The next prime is 66444857393. The reversal of 66444857361 is 16375844466.

The square root of 66444857361 is 257769.

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

66444857361 is a `hidden beast` number, since 6 + 6 + 4 + 4 + 4 + 8 + 573 + 61 = 666.

It is not a de Polignac number, because 66444857361 - 2²⁵ = 66411302929 is a prime.

It is a junction number, because it is equal to n+sod(n) for n = 66444857298 and 66444857307.

It is not an unprimeable number, because it can be changed into a prime (66444857161) by changing a digit.

It is a polite number, since it can be written in 20 ways as a sum of consecutive naturals, for example, 6954990 + ... + 6964536.

Almost surely, 2^66444857361 is an apocalyptic number.

66444857361 is the 257769-th square number.

66444857361 is the 128885-th centered octagonal number.

It is an amenable number.

66444857361 is a deficient number, since it is larger than the sum of its proper divisors (33187292040).

66444857361 is an frugal number, since it uses more digits than its factorization.

66444857361 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 19112 (or 9550 counting only the distinct ones).

The product of its digits is 11612160, while the sum is 54.

The spelling of 66444857361 in words is "sixty-six billion, four hundred forty-four million, eight hundred fifty-seven thousand, three hundred sixty-one".