13721608557 has 6 divisors (see below), whose sum is σ = 19820101262. Its totient is φ = 9147739032.

The previous prime is 13721608543. The next prime is 13721608591. The reversal of 13721608557 is 75580612731.

It is a happy number.

13721608557 is a `hidden beast` number, since 1 + 37 + 2 + 1 + 60 + 8 + 557 = 666.

It can be written as a sum of positive squares in only one way, i.e., 9731033316 + 3990575241 = 98646^2 + 63171^2 .

It is not a de Polignac number, because 13721608557 - 2⁴ = 13721608541 is a prime.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (13721608757) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (19) of ones.

It is a polite number, since it can be written in 5 ways as a sum of consecutive naturals, for example, 762311578 + ... + 762311595.

Almost surely, 2^13721608557 is an apocalyptic number.

It is an amenable number.

13721608557 is a deficient number, since it is larger than the sum of its proper divisors (6098492705).

13721608557 is a wasteful number, since it uses less digits than its factorization.

13721608557 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1524623179 (or 1524623176 counting only the distinct ones).

The product of its (nonzero) digits is 352800, while the sum is 45.

The spelling of 13721608557 in words is "thirteen billion, seven hundred twenty-one million, six hundred eight thousand, five hundred fifty-seven".