1311231240 has 160 divisors (see below), whose sum is σ = 4807978560. Its totient is φ = 317865600.

The previous prime is 1311231221. The next prime is 1311231253. The reversal of 1311231240 is 421321131.

1311231240 is a `hidden beast` number, since 1 + 311 + 2 + 312 + 40 = 666.

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

It is an unprimeable number.

It is a polite number, since it can be written in 39 ways as a sum of consecutive naturals, for example, 17245 + ... + 54035.

It is an arithmetic number, because the mean of its divisors is an integer number (30049866).

Almost surely, 2^1311231240 is an apocalyptic number.

1311231240 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 1311231240, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (2403989280).

1311231240 is an abundant number, since it is smaller than the sum of its proper divisors (3496747320).

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

1311231240 is a wasteful number, since it uses less digits than its factorization.

1311231240 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 36825 (or 36812 counting only the distinct ones).

The product of its (nonzero) digits is 144, while the sum is 18.

The square root of 1311231240 is about 36210.9270800956. The cubic root of 1311231240 is about 1094.5268738528.

Adding to 1311231240 its reverse (421321131), we get a palindrome (1732552371).

The spelling of 1311231240 in words is "one billion, three hundred eleven million, two hundred thirty-one thousand, two hundred forty".