1287009 has 10 divisors (see below), whose sum is σ = 1922690. Its totient is φ = 857952.

The previous prime is 1287007. The next prime is 1287047. The reversal of 1287009 is 9007821.

It can be written as a sum of positive squares in only one way, i.e., 944784 + 342225 = 972^2 + 585^2 .

It is not a de Polignac number, because 1287009 - 2¹ = 1287007 is a prime.

It is a Harshad number since it is a multiple of its sum of digits (27).

It is an Ulam number.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (1287007) by changing a digit.

It is a polite number, since it can be written in 9 ways as a sum of consecutive naturals, for example, 7864 + ... + 8025.

It is an arithmetic number, because the mean of its divisors is an integer number (192269).

2^1287009 is an apocalyptic number.

It is an amenable number.

1287009 is a deficient number, since it is larger than the sum of its proper divisors (635681).

1287009 is an equidigital number, since it uses as much as digits as its factorization.

1287009 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 15901 (or 15892 counting only the distinct ones).

The product of its (nonzero) digits is 1008, while the sum is 27.

The square root of 1287009 is about 1134.4641907085. The cubic root of 1287009 is about 108.7745247899.

The spelling of 1287009 in words is "one million, two hundred eighty-seven thousand, nine".