13531203521 has 4 divisors (see below), whose sum is σ = 14761312944. Its totient is φ = 12301094100.

The previous prime is 13531203481. The next prime is 13531203541. The reversal of 13531203521 is 12530213531.

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, and also an emirpimes, since its reverse is a distinct semiprime: 12530213531 = 11 ⋅1139110321.

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-13531203521 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (13531203541) 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, 615054695 + ... + 615054716.

It is an arithmetic number, because the mean of its divisors is an integer number (3690328236).

Almost surely, 2^13531203521 is an apocalyptic number.

13531203521 is a gapful number since it is divisible by the number (11) formed by its first and last digit.

It is an amenable number.

13531203521 is a deficient number, since it is larger than the sum of its proper divisors (1230109423).

13531203521 is a wasteful number, since it uses less digits than its factorization.

13531203521 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1230109422.

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

The spelling of 13531203521 in words is "thirteen billion, five hundred thirty-one million, two hundred three thousand, five hundred twenty-one".