1966745393649 has 21 divisors (see below), whose sum is σ = 2948825929339. Its totient is φ = 1311138352440.

The previous prime is 1966745393497. The next prime is 1966745393659. The reversal of 1966745393649 is 9463935476691.

The square root of 1966745393649 is 1402407.

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

1966745393649 is a `hidden beast` number, since 19 + 6 + 6 + 7 + 4 + 539 + 36 + 49 = 666.

It can be written as a sum of positive squares in only one way, i.e., 63173303649 + 1903572090000 = 251343^2 + 1379700^2 .

It is not a de Polignac number, because 1966745393649 - 2¹¹ = 1966745391601 is a prime.

It is a Duffinian number.

It is a Curzon number.

It is not an unprimeable number, because it can be changed into a prime (1966745393659) 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, 37839019 + ... + 37890959.

Almost surely, 2^{1966745393649} is an apocalyptic number.

1966745393649 is the 1402407-th square number.

1966745393649 is the 701204-th centered octagonal number.

It is an amenable number.

1966745393649 is a deficient number, since it is larger than the sum of its proper divisors (982080535690).

1966745393649 is an frugal number, since it uses more digits than its factorization.

1966745393649 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 103900 (or 51944 counting only the distinct ones).

The product of its digits is 793618560, while the sum is 72.

The spelling of 1966745393649 in words is "one trillion, nine hundred sixty-six billion, seven hundred forty-five million, three hundred ninety-three thousand, six hundred forty-nine".