1231311144 has 64 divisors (see below), whose sum is σ = 3537555840. Its totient is φ = 349850880.

The previous prime is 1231311127. The next prime is 1231311161. The reversal of 1231311144 is 4411131321.

It is an interprime number because it is at equal distance from previous prime (1231311127) and next prime (1231311161).

It is a super-2 number, since 2×1231311144² = 3032254266677177472, which contains 22 as substring.

It is a Harshad number since it is a multiple of its sum of digits (21).

It is a nude number because it is divisible by every one of its digits.

It is a self number, because there is not a number n which added to its sum of digits gives 1231311144.

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 10162 + ... + 50654.

It is an arithmetic number, because the mean of its divisors is an integer number (55274310).

Almost surely, 2^1231311144 is an apocalyptic number.

1231311144 is a gapful number since it is divisible by the number (14) 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 1231311144, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (1768777920).

1231311144 is an abundant number, since it is smaller than the sum of its proper divisors (2306244696).

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

1231311144 is a wasteful number, since it uses less digits than its factorization.

1231311144 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 40690 (or 40686 counting only the distinct ones).

The product of its digits is 288, while the sum is 21.

The square root of 1231311144 is about 35090.0433741539. The cubic root of 1231311144 is about 1071.8218428409.

Adding to 1231311144 its reverse (4411131321), we get a palindrome (5642442465).

The spelling of 1231311144 in words is "one billion, two hundred thirty-one million, three hundred eleven thousand, one hundred forty-four".