1311231505020 has 384 divisors, whose sum is σ = 3919243345920. Its totient is φ = 327146465280.

The previous prime is 1311231504997. The next prime is 1311231505069. The reversal of 1311231505020 is 205051321131.

It is a congruent number.

It is an unprimeable number.

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, 1333907449 + ... + 1333908431.

It is an arithmetic number, because the mean of its divisors is an integer number (10206362880).

Almost surely, 2^{1311231505020} is an apocalyptic number.

1311231505020 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 1311231505020, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (1959621672960).

1311231505020 is an abundant number, since it is smaller than the sum of its proper divisors (2608011840900).

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

1311231505020 is a wasteful number, since it uses less digits than its factorization.

1311231505020 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1305 (or 1303 counting only the distinct ones).

The product of its (nonzero) digits is 900, while the sum is 24.

Adding to 1311231505020 its reverse (205051321131), we get a palindrome (1516282826151).

The spelling of 1311231505020 in words is "one trillion, three hundred eleven billion, two hundred thirty-one million, five hundred five thousand, twenty".