1311840 has 72 divisors (see below), whose sum is σ = 4481568. Its totient is φ = 349440.

The previous prime is 1311829. The next prime is 1311847. The reversal of 1311840 is 481131.

It is a tau number, because it is divible by the number of its divisors (72).

It is a Harshad number since it is a multiple of its sum of digits (18).

It is a nialpdrome in base 12.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (1311847) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (5) of ones.

It is a polite number, since it can be written in 11 ways as a sum of consecutive naturals, for example, 985 + ... + 1895.

It is an arithmetic number, because the mean of its divisors is an integer number (62244).

2^1311840 is an apocalyptic number.

1311840 is a gapful number since it is divisible by the number (10) formed by its first and last digit.

It is an amenable number.

It is a practical number, because each smaller number is the sum of distinct divisors of 1311840, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (2240784).

1311840 is an abundant number, since it is smaller than the sum of its proper divisors (3169728).

It is a pseudoperfect number, because it is the sum of a subset of its proper divisors.

1311840 is a wasteful number, since it uses less digits than its factorization.

1311840 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 932 (or 921 counting only the distinct ones).

The product of its (nonzero) digits is 96, while the sum is 18.

The square root of 1311840 is about 1145.3558399030. The cubic root of 1311840 is about 109.4696231495.

Adding to 1311840 its reverse (481131), we get a palindrome (1792971).

The spelling of 1311840 in words is "one million, three hundred eleven thousand, eight hundred forty".