1287817 has 2 divisors, whose sum is σ = 1287818. Its totient is φ = 1287816.

The previous prime is 1287799. The next prime is 1287821. The reversal of 1287817 is 7187821.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 952576 + 335241 = 976^2 + 579^2 .

It is a cyclic number.

It is not a de Polignac number, because 1287817 - 2¹⁵ = 1255049 is a prime.

1287817 is a lucky number.

It is not a weakly prime, because it can be changed into another prime (1287857) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 643908 + 643909.

It is an arithmetic number, because the mean of its divisors is an integer number (643909).

2^1287817 is an apocalyptic number.

It is an amenable number.

1287817 is a deficient number, since it is larger than the sum of its proper divisors (1).

1287817 is an equidigital number, since it uses as much as digits as its factorization.

1287817 is an evil number, because the sum of its binary digits is even.

The product of its digits is 6272, while the sum is 34.

The square root of 1287817 is about 1134.8202500837. The cubic root of 1287817 is about 108.7972833538.

The spelling of 1287817 in words is "one million, two hundred eighty-seven thousand, eight hundred seventeen".