1066140916681 has 3 divisors (see below), whose sum is σ = 1066141949223. Its totient is φ = 1066139884140.

The previous prime is 1066140916649. The next prime is 1066140916699. The reversal of 1066140916681 is 1866190416601.

The square root of 1066140916681 is 1032541.

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

It is a semiprime because it is the product of two primes, and also a brilliant number, because the two primes have the same length.

It can be written as a sum of positive squares in only one way, i.e., 860551220281 + 205589696400 = 927659^2 + 453420^2 .

It is not a de Polignac number, because 1066140916681 - 2⁵ = 1066140916649 is a prime.

It is a super-2 number, since 2×1066140916681² (a number of 25 digits) contains 22 as substring.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (1066110916681) by changing a digit.

It is a polite number, since it can be written in 2 ways as a sum of consecutive naturals, for example, 516271 + ... + 1548811.

It is an arithmetic number, because the mean of its divisors is an integer number (355380649741).

Almost surely, 2^{1066140916681} is an apocalyptic number.

1066140916681 is the 1032541-st square number.

1066140916681 is the 516271-st centered octagonal number.

It is an amenable number.

1066140916681 is a deficient number, since it is larger than the sum of its proper divisors (1032542).

1066140916681 is an frugal number, since it uses more digits than its factorization.

1066140916681 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 2065082 (or 1032541 counting only the distinct ones).

The product of its (nonzero) digits is 373248, while the sum is 49.

Multiplying 1066140916681 by its sum of digits (49), we get a square (52240904917369 = 7227787²).

The spelling of 1066140916681 in words is "one trillion, sixty-six billion, one hundred forty million, nine hundred sixteen thousand, six hundred eighty-one".