13721382581 has 2 divisors, whose sum is σ = 13721382582. Its totient is φ = 13721382580.

The previous prime is 13721382503. The next prime is 13721382599. The reversal of 13721382581 is 18528312731.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 12621399025 + 1099983556 = 112345^2 + 33166^2 .

It is a cyclic number.

It is not a de Polignac number, because 13721382581 - 2¹⁸ = 13721120437 is a prime.

It is a super-2 number, since 2×13721382581² (a number of 21 digits) contains 22 as substring.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (13721382881) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 6860691290 + 6860691291.

It is an arithmetic number, because the mean of its divisors is an integer number (6860691291).

Almost surely, 2^13721382581 is an apocalyptic number.

It is an amenable number.

13721382581 is a deficient number, since it is larger than the sum of its proper divisors (1).

13721382581 is an equidigital number, since it uses as much as digits as its factorization.

13721382581 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 80640, while the sum is 41.

The spelling of 13721382581 in words is "thirteen billion, seven hundred twenty-one million, three hundred eighty-two thousand, five hundred eighty-one".