1311042440 has 128 divisors (see below), whose sum is σ = 3157056000. Its totient is φ = 489151488.

The previous prime is 1311042433. The next prime is 1311042449. The reversal of 1311042440 is 442401131.

It is a Harshad number since it is a multiple of its sum of digits (20).

It is not an unprimeable number, because it can be changed into a prime (1311042449) by changing a digit.

It is a polite number, since it can be written in 31 ways as a sum of consecutive naturals, for example, 7578194 + ... + 7578366.

It is an arithmetic number, because the mean of its divisors is an integer number (24664500).

Almost surely, 2^1311042440 is an apocalyptic number.

1311042440 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 1311042440, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (1578528000).

1311042440 is an abundant number, since it is smaller than the sum of its proper divisors (1846013560).

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

1311042440 is a wasteful number, since it uses less digits than its factorization.

1311042440 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 399 (or 395 counting only the distinct ones).

The product of its (nonzero) digits is 384, while the sum is 20.

The square root of 1311042440 is about 36208.3200383558. The cubic root of 1311042440 is about 1094.4743388546.

Adding to 1311042440 its reverse (442401131), we get a palindrome (1753443571).

The spelling of 1311042440 in words is "one billion, three hundred eleven million, forty-two thousand, four hundred forty".