1287985 has 8 divisors (see below), whose sum is σ = 1555560. Its totient is φ = 1023744.

The previous prime is 1287983. The next prime is 1287989. The reversal of 1287985 is 5897821.

It can be written as a sum of positive squares in 4 ways, for example, as 204304 + 1083681 = 452^2 + 1041^2 .

It is a sphenic number, since it is the product of 3 distinct primes.

It is a cyclic number.

It is not a de Polignac number, because 1287985 - 2¹ = 1287983 is a prime.

It is not an unprimeable number, because it can be changed into a prime (1287983) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 121 + ... + 1609.

It is an arithmetic number, because the mean of its divisors is an integer number (194445).

2^1287985 is an apocalyptic number.

It is an amenable number.

1287985 is a deficient number, since it is larger than the sum of its proper divisors (267575).

1287985 is a wasteful number, since it uses less digits than its factorization.

1287985 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1667.

The product of its digits is 40320, while the sum is 40.

The square root of 1287985 is about 1134.8942682030. The cubic root of 1287985 is about 108.8020141369.

The spelling of 1287985 in words is "one million, two hundred eighty-seven thousand, nine hundred eighty-five".