1287409 has 4 divisors (see below), whose sum is σ = 1298916. Its totient is φ = 1275904.

The previous prime is 1287401. The next prime is 1287431. The reversal of 1287409 is 9047821.

It is a semiprime because it is the product of two primes.

It can be written as a sum of positive squares in 2 ways, for example, as 394384 + 893025 = 628^2 + 945^2 .

It is a cyclic number.

It is not a de Polignac number, because 1287409 - 2³ = 1287401 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (1287401) 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 3 ways as a sum of consecutive naturals, for example, 5584 + ... + 5809.

It is an arithmetic number, because the mean of its divisors is an integer number (324729).

2^1287409 is an apocalyptic number.

It is an amenable number.

1287409 is a deficient number, since it is larger than the sum of its proper divisors (11507).

1287409 is a wasteful number, since it uses less digits than its factorization.

1287409 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 11506.

The product of its (nonzero) digits is 4032, while the sum is 31.

The square root of 1287409 is about 1134.6404716914. The cubic root of 1287409 is about 108.7857925959.

The spelling of 1287409 in words is "one million, two hundred eighty-seven thousand, four hundred nine".