1287997 has 2 divisors, whose sum is σ = 1287998.
Its totient is φ = 1287996.
The previous prime is 1287989. The next prime is 1288003. The reversal of 1287997 is 7997821.
It is a happy number.
It is a strong prime.
It can be written as a sum of positive squares in only one way, i.e., 1279161 + 8836 = 1131^2 + 94^2
It is a cyclic number.
It is not a de Polignac number, because 1287997 - 23 = 1287989 is a prime.
It is a congruent number.
It is not a weakly prime, because it can be changed into another prime (1287917) by changing a digit.
It is a pernicious number, because its binary representation contains a prime number (13) of ones.
It is a polite number, since it can be written as a sum of consecutive naturals, namely, 643998 + 643999.
It is an arithmetic number, because the mean of its divisors is an integer number (643999).
21287997 is an apocalyptic number.
It is an amenable number.
1287997 is a deficient number, since it is larger than the sum of its proper divisors (1).
1287997 is an equidigital number, since it uses as much as digits as its factorization.
1287997 is an odious number, because the sum of its binary digits is odd.
The product of its digits is 63504, while the sum is 43.
The square root of 1287997 is about 1134.8995550268.
The cubic root of 1287997 is about 108.8023520343.
The spelling of 1287997 in words is "one million, two hundred eighty-seven thousand, nine hundred ninety-seven".