1331287 has 4 divisors (see below), whose sum is σ = 1409616. Its totient is φ = 1252960.

The previous prime is 1331279. The next prime is 1331293. The reversal of 1331287 is 7821331.

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

It is a cyclic number.

It is not a de Polignac number, because 1331287 - 2³ = 1331279 is a prime.

It is an Ulam number.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (1331207) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 39139 + ... + 39172.

It is an arithmetic number, because the mean of its divisors is an integer number (352404).

2^1331287 is an apocalyptic number.

1331287 is a gapful number since it is divisible by the number (17) formed by its first and last digit.

1331287 is a deficient number, since it is larger than the sum of its proper divisors (78329).

1331287 is an equidigital number, since it uses as much as digits as its factorization.

1331287 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 78328.

The product of its digits is 1008, while the sum is 25.

The square root of 1331287 is about 1153.8141098115. The cubic root of 1331287 is about 110.0079057679.

It can be divided in two parts, 133 and 1287, that multiplied together give a palindrome (171171).

The spelling of 1331287 in words is "one million, three hundred thirty-one thousand, two hundred eighty-seven".