13021335521 has 4 divisors (see below), whose sum is σ = 13787296452. Its totient is φ = 12255374592.

The previous prime is 13021335517. The next prime is 13021335557. The reversal of 13021335521 is 12553312031.

It is a semiprime because it is the product of two primes, and also an emirpimes, since its reverse is a distinct semiprime: 12553312031 = 13 ⋅965639387.

It can be written as a sum of positive squares in 2 ways, for example, as 10816000000 + 2205335521 = 104000^2 + 46961^2 .

It is a cyclic number.

It is not a de Polignac number, because 13021335521 - 2² = 13021335517 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (13021535521) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 382980440 + ... + 382980473.

It is an arithmetic number, because the mean of its divisors is an integer number (3446824113).

Almost surely, 2^13021335521 is an apocalyptic number.

It is an amenable number.

13021335521 is a deficient number, since it is larger than the sum of its proper divisors (765960931).

13021335521 is an equidigital number, since it uses as much as digits as its factorization.

13021335521 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 765960930.

The product of its (nonzero) digits is 2700, while the sum is 26.

Adding to 13021335521 its reverse (12553312031), we get a palindrome (25574647552).

The spelling of 13021335521 in words is "thirteen billion, twenty-one million, three hundred thirty-five thousand, five hundred twenty-one".