13381538581 has 8 divisors (see below), whose sum is σ = 13638022200. Its totient is φ = 13127486400.

The previous prime is 13381538561. The next prime is 13381538587. The reversal of 13381538581 is 18583518331.

It can be written as a sum of positive squares in 4 ways, for example, as 10405836081 + 2975702500 = 102009^2 + 54550^2 .

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 13381538581 - 2¹⁷ = 13381407509 is a prime.

It is a super-2 number, since 2×13381538581² (a number of 21 digits) contains 22 as substring.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (13381538587) 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, 596746 + ... + 618763.

It is an arithmetic number, because the mean of its divisors is an integer number (1704752775).

Almost surely, 2^13381538581 is an apocalyptic number.

It is an amenable number.

13381538581 is a deficient number, since it is larger than the sum of its proper divisors (256483619).

13381538581 is a wasteful number, since it uses less digits than its factorization.

13381538581 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1215719.

The product of its digits is 345600, while the sum is 46.

The spelling of 13381538581 in words is "thirteen billion, three hundred eighty-one million, five hundred thirty-eight thousand, five hundred eighty-one".