1231311323220 has 384 divisors, whose sum is σ = 3916470362112. Its totient is φ = 286474752000.

The previous prime is 1231311323219. The next prime is 1231311323227. The reversal of 1231311323220 is 223231131321.

It is a super-2 number, since 2×1231311323220² (a number of 25 digits) contains 22 as substring.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (1231311323227) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (23) of ones.

It is a polite number, since it can be written in 127 ways as a sum of consecutive naturals, for example, 335231304 + ... + 335234976.

It is an arithmetic number, because the mean of its divisors is an integer number (10199141568).

Almost surely, 2^{1231311323220} is an apocalyptic number.

1231311323220 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 1231311323220, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (1958235181056).

1231311323220 is an abundant number, since it is smaller than the sum of its proper divisors (2685159038892).

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

1231311323220 is a wasteful number, since it uses less digits than its factorization.

1231311323220 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 3951 (or 3949 counting only the distinct ones).

The product of its (nonzero) digits is 1296, while the sum is 24.

Adding to 1231311323220 its reverse (223231131321), we get a palindrome (1454542454541).

The spelling of 1231311323220 in words is "one trillion, two hundred thirty-one billion, three hundred eleven million, three hundred twenty-three thousand, two hundred twenty".