1556115397 has 2 divisors, whose sum is σ = 1556115398. Its totient is φ = 1556115396.

The previous prime is 1556115373. The next prime is 1556115443. The reversal of 1556115397 is 7935116551.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 1283502276 + 272613121 = 35826^2 + 16511^2 .

It is an emirp because it is prime and its reverse (7935116551) is a distict prime.

It is a cyclic number.

It is not a de Polignac number, because 1556115397 - 2²⁷ = 1421897669 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (1556115097) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 778057698 + 778057699.

It is an arithmetic number, because the mean of its divisors is an integer number (778057699).

Almost surely, 2^1556115397 is an apocalyptic number.

It is an amenable number.

1556115397 is a deficient number, since it is larger than the sum of its proper divisors (1).

1556115397 is an equidigital number, since it uses as much as digits as its factorization.

1556115397 is an evil number, because the sum of its binary digits is even.

The product of its digits is 141750, while the sum is 43.

The square root of 1556115397 is about 39447.6285345520. The cubic root of 1556115397 is about 1158.8145333217.

The spelling of 1556115397 in words is "one billion, five hundred fifty-six million, one hundred fifteen thousand, three hundred ninety-seven".