15115593478781 has 2 divisors, whose sum is σ = 15115593478782. Its totient is φ = 15115593478780.

The previous prime is 15115593478763. The next prime is 15115593478841. The reversal of 15115593478781 is 18787439551151.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 13212134522500 + 1903458956281 = 3634850^2 + 1379659^2 .

It is an emirp because it is prime and its reverse (18787439551151) is a distict prime.

It is a cyclic number.

It is not a de Polignac number, because 15115593478781 - 2⁶ = 15115593478717 is a prime.

It is a super-3 number, since 3×15115593478781³ (a number of 41 digits) contains 333 as substring. Note that it is a super-d number also for d = 2.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (15115593478981) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (29) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 7557796739390 + 7557796739391.

It is an arithmetic number, because the mean of its divisors is an integer number (7557796739391).

Almost surely, 2^{15115593478781} is an apocalyptic number.

It is an amenable number.

15115593478781 is a deficient number, since it is larger than the sum of its proper divisors (1).

15115593478781 is an equidigital number, since it uses as much as digits as its factorization.

15115593478781 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 42336000, while the sum is 65.

The spelling of 15115593478781 in words is "fifteen trillion, one hundred fifteen billion, five hundred ninety-three million, four hundred seventy-eight thousand, seven hundred eighty-one".