1311985 has 8 divisors (see below), whose sum is σ = 1582056. Its totient is φ = 1044480.

The previous prime is 1311971. The next prime is 1311991. The reversal of 1311985 is 5891131.

It can be written as a sum of positive squares in 4 ways, for example, as 535824 + 776161 = 732^2 + 881^2 .

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

It is not a de Polignac number, because 1311985 - 2⁷ = 1311857 is a prime.

It is a Duffinian number.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 775 + ... + 1795.

It is an arithmetic number, because the mean of its divisors is an integer number (197757).

2^1311985 is an apocalyptic number.

It is an amenable number.

1311985 is a deficient number, since it is larger than the sum of its proper divisors (270071).

1311985 is a wasteful number, since it uses less digits than its factorization.

1311985 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1283.

The product of its digits is 1080, while the sum is 28.

The square root of 1311985 is about 1145.4191372594. The cubic root of 1311985 is about 109.4736562914.

It can be divided in two parts, 131 and 1985, that added together give a square (2116 = 46²).

The spelling of 1311985 in words is "one million, three hundred eleven thousand, nine hundred eighty-five".