1287798557 has 2 divisors, whose sum is σ = 1287798558. Its totient is φ = 1287798556.

The previous prime is 1287798527. The next prime is 1287798571. The reversal of 1287798557 is 7558977821.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 1257482521 + 30316036 = 35461^2 + 5506^2 .

It is a cyclic number.

It is not a de Polignac number, because 1287798557 - 2⁸ = 1287798301 is a prime.

It is a super-2 number, since 2×1287798557² = 3316850246822564498, which contains 22 as substring.

It is a junction number, because it is equal to n+sod(n) for n = 1287798496 and 1287798505.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (1287798527) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 643899278 + 643899279.

It is an arithmetic number, because the mean of its divisors is an integer number (643899279).

Almost surely, 2^1287798557 is an apocalyptic number.

It is an amenable number.

1287798557 is a deficient number, since it is larger than the sum of its proper divisors (1).

1287798557 is an equidigital number, since it uses as much as digits as its factorization.

1287798557 is an evil number, because the sum of its binary digits is even.

The product of its digits is 9878400, while the sum is 59.

The square root of 1287798557 is about 35885.9102852359. The cubic root of 1287798557 is about 1087.9676398450.

The spelling of 1287798557 in words is "one billion, two hundred eighty-seven million, seven hundred ninety-eight thousand, five hundred fifty-seven".