12947778501557 has 2 divisors, whose sum is σ = 12947778501558. Its totient is φ = 12947778501556.

The previous prime is 12947778501503. The next prime is 12947778501589. The reversal of 12947778501557 is 75510587774921.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 6939857878321 + 6007920623236 = 2634361^2 + 2451106^2 .

It is a cyclic number.

It is not a de Polignac number, because 12947778501557 - 2²⁴ = 12947761724341 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (12947778507557) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 6473889250778 + 6473889250779.

It is an arithmetic number, because the mean of its divisors is an integer number (6473889250779).

Almost surely, 2^{12947778501557} is an apocalyptic number.

It is an amenable number.

12947778501557 is a deficient number, since it is larger than the sum of its proper divisors (1).

12947778501557 is an equidigital number, since it uses as much as digits as its factorization.

12947778501557 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 172872000, while the sum is 68.

The spelling of 12947778501557 in words is "twelve trillion, nine hundred forty-seven billion, seven hundred seventy-eight million, five hundred one thousand, five hundred fifty-seven".