1287309 has 8 divisors (see below), whose sum is σ = 1722112. Its totient is φ = 855360.

The previous prime is 1287289. The next prime is 1287323. The reversal of 1287309 is 9037821.

It is a happy number.

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

It is not a de Polignac number, because 1287309 - 2⁹ = 1286797 is a prime.

It is a super-2 number, since 2×1287309² = 3314328922962, which contains 22 as substring.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (1287329) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 804 + ... + 1794.

It is an arithmetic number, because the mean of its divisors is an integer number (215264).

2^1287309 is an apocalyptic number.

It is an amenable number.

1287309 is a deficient number, since it is larger than the sum of its proper divisors (434803).

1287309 is an equidigital number, since it uses as much as digits as its factorization.

1287309 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1427.

The product of its (nonzero) digits is 3024, while the sum is 30.

The square root of 1287309 is about 1134.5964040133. The cubic root of 1287309 is about 108.7829758632.

It can be divided in two parts, 1287 and 309, that added together give a triangular number (1596 = T₅₆).

The spelling of 1287309 in words is "one million, two hundred eighty-seven thousand, three hundred nine".