1231115515520 has 128 divisors (see below), whose sum is σ = 3211980065280. Its totient is φ = 447498956800.

The previous prime is 1231115515457. The next prime is 1231115515571. The reversal of 1231115515520 is 255155111321.

It is a tau number, because it is divible by the number of its divisors (128).

It is a Harshad number since it is a multiple of its sum of digits (32).

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (19) of ones.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 18206894 + ... + 18274386.

It is an arithmetic number, because the mean of its divisors is an integer number (25093594260).

Almost surely, 2^{1231115515520} is an apocalyptic number.

1231115515520 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 1231115515520, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (1605990032640).

1231115515520 is an abundant number, since it is smaller than the sum of its proper divisors (1980864549760).

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

1231115515520 is a wasteful number, since it uses less digits than its factorization.

1231115515520 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 70114 (or 70102 counting only the distinct ones).

The product of its (nonzero) digits is 7500, while the sum is 32.

The spelling of 1231115515520 in words is "one trillion, two hundred thirty-one billion, one hundred fifteen million, five hundred fifteen thousand, five hundred twenty".