13540023521 has 8 divisors (see below), whose sum is σ = 13699026600. Its totient is φ = 13381708032.

The previous prime is 13540023451. The next prime is 13540023533. The reversal of 13540023521 is 12532004531.

It is a happy number.

It can be written as a sum of positive squares in 4 ways, for example, as 2112413521 + 11427610000 = 45961^2 + 106900^2 .

It is a sphenic number, since it is the product of 3 distinct primes.

It is a cyclic number.

It is not a de Polignac number, because 13540023521 - 2²² = 13535829217 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (13540023551) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 132230 + ... + 211103.

It is an arithmetic number, because the mean of its divisors is an integer number (1712378325).

Almost surely, 2^13540023521 is an apocalyptic number.

It is an amenable number.

13540023521 is a deficient number, since it is larger than the sum of its proper divisors (159003079).

13540023521 is a wasteful number, since it uses less digits than its factorization.

13540023521 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 343795.

The product of its (nonzero) digits is 3600, while the sum is 26.

The spelling of 13540023521 in words is "thirteen billion, five hundred forty million, twenty-three thousand, five hundred twenty-one".