1331806013521 has 3 divisors (see below), whose sum is σ = 1331807167561. Its totient is φ = 1331804859482.

The previous prime is 1331806013443. The next prime is 1331806013563. The reversal of 1331806013521 is 1253106081331.

The square root of 1331806013521 is 1154039.

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 is not a de Polignac number, because 1331806013521 - 2¹⁵ = 1331805980753 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (1331800013521) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written in 2 ways as a sum of consecutive naturals, for example, 577020 + ... + 1731058.

Almost surely, 2^{1331806013521} is an apocalyptic number.

1331806013521 is the 1154039-th square number.

1331806013521 is the 577020-th centered octagonal number.

It is an amenable number.

1331806013521 is a deficient number, since it is larger than the sum of its proper divisors (1154040).

1331806013521 is an frugal number, since it uses more digits than its factorization.

1331806013521 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 2308078 (or 1154039 counting only the distinct ones).

The product of its (nonzero) digits is 12960, while the sum is 34.

The spelling of 1331806013521 in words is "one trillion, three hundred thirty-one billion, eight hundred six million, thirteen thousand, five hundred twenty-one".