13978356517 has 2 divisors, whose sum is σ = 13978356518. Its totient is φ = 13978356516.

The previous prime is 13978356493. The next prime is 13978356571. The reversal of 13978356517 is 71565387931.

Together with next prime (13978356571) it forms an Ormiston pair, because they use the same digits, order apart.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 11013662916 + 2964693601 = 104946^2 + 54449^2 .

It is a cyclic number.

It is not a de Polignac number, because 13978356517 - 2¹⁹ = 13977832229 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (13978359517) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 6989178258 + 6989178259.

It is an arithmetic number, because the mean of its divisors is an integer number (6989178259).

Almost surely, 2^13978356517 is an apocalyptic number.

It is an amenable number.

13978356517 is a deficient number, since it is larger than the sum of its proper divisors (1).

13978356517 is an equidigital number, since it uses as much as digits as its factorization.

13978356517 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 4762800, while the sum is 55.

The spelling of 13978356517 in words is "thirteen billion, nine hundred seventy-eight million, three hundred fifty-six thousand, five hundred seventeen".