20131231240 has 32 divisors (see below), whose sum is σ = 46400036760. Its totient is φ = 7856089600.

The previous prime is 20131231213. The next prime is 20131231249. The reversal of 20131231240 is 4213213102.

It is a happy number.

It can be written as a sum of positive squares in 4 ways, for example, as 7131126916 + 13000104324 = 84446^2 + 114018^2 .

It is not an unprimeable number, because it can be changed into a prime (20131231249) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 6135931 + ... + 6139210.

Almost surely, 2^20131231240 is an apocalyptic number.

20131231240 is a gapful number since it is divisible by the number (20) formed by its first and last digit.

It is an amenable number.

20131231240 is an abundant number, since it is smaller than the sum of its proper divisors (26268805520).

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

20131231240 is a wasteful number, since it uses less digits than its factorization.

20131231240 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 12275193 (or 12275189 counting only the distinct ones).

The product of its (nonzero) digits is 288, while the sum is 19.

Adding to 20131231240 its reverse (4213213102), we get a palindrome (24344444342).

The spelling of 20131231240 in words is "twenty billion, one hundred thirty-one million, two hundred thirty-one thousand, two hundred forty".