13561043557 has 2 divisors, whose sum is σ = 13561043558. Its totient is φ = 13561043556.

The previous prime is 13561043537. The next prime is 13561043579. The reversal of 13561043557 is 75534016531.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 10394618116 + 3166425441 = 101954^2 + 56271^2 .

It is a cyclic number.

It is not a de Polignac number, because 13561043557 - 2²⁷ = 13426825829 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (13561043537) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 6780521778 + 6780521779.

It is an arithmetic number, because the mean of its divisors is an integer number (6780521779).

Almost surely, 2^13561043557 is an apocalyptic number.

It is an amenable number.

13561043557 is a deficient number, since it is larger than the sum of its proper divisors (1).

13561043557 is an equidigital number, since it uses as much as digits as its factorization.

13561043557 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 189000, while the sum is 40.

The spelling of 13561043557 in words is "thirteen billion, five hundred sixty-one million, forty-three thousand, five hundred fifty-seven".