13531121521 has 4 divisors (see below), whose sum is σ = 13967609344. Its totient is φ = 13094633700.

The previous prime is 13531121509. The next prime is 13531121533. The reversal of 13531121521 is 12512113531.

It is a semiprime because it is the product of two primes, and also a Blum integer, because the two primes are equal to 3 mod 4.

It is an interprime number because it is at equal distance from previous prime (13531121509) and next prime (13531121533).

It is a cyclic number.

It is not a de Polignac number, because 13531121521 - 2¹³ = 13531113329 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (13531121551) 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, 218243865 + ... + 218243926.

It is an arithmetic number, because the mean of its divisors is an integer number (3491902336).

Almost surely, 2^13531121521 is an apocalyptic number.

It is an amenable number.

13531121521 is a deficient number, since it is larger than the sum of its proper divisors (436487823).

13531121521 is an equidigital number, since it uses as much as digits as its factorization.

13531121521 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 436487822.

The product of its digits is 900, while the sum is 25.

The spelling of 13531121521 in words is "thirteen billion, five hundred thirty-one million, one hundred twenty-one thousand, five hundred twenty-one".