1312123320 has 256 divisors, whose sum is σ = 4617907200. Its totient is φ = 330739200.

The previous prime is 1312123301. The next prime is 1312123327. The reversal of 1312123320 is 233212131.

1312123320 is a `hidden beast` number, since 131 + 212 + 3 + 320 = 666.

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

It is a junction number, because it is equal to n+sod(n) for n = 1312123293 and 1312123302.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (1312123327) by changing a digit.

It is a polite number, since it can be written in 63 ways as a sum of consecutive naturals, for example, 2508579 + ... + 2509101.

It is an arithmetic number, because the mean of its divisors is an integer number (18038700).

Almost surely, 2^1312123320 is an apocalyptic number.

1312123320 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 1312123320, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (2308953600).

1312123320 is an abundant number, since it is smaller than the sum of its proper divisors (3305783880).

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

1312123320 is a wasteful number, since it uses less digits than its factorization.

1312123320 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 667 (or 657 counting only the distinct ones).

The product of its (nonzero) digits is 216, while the sum is 18.

The square root of 1312123320 is about 36223.2428145245. The cubic root of 1312123320 is about 1094.7750335364.

Adding to 1312123320 its reverse (233212131), we get a palindrome (1545335451).

The spelling of 1312123320 in words is "one billion, three hundred twelve million, one hundred twenty-three thousand, three hundred twenty".