1321538416128 has 720 divisors, whose sum is σ = 4673834605440. Its totient is φ = 365170913280.

The previous prime is 1321538416111. The next prime is 1321538416129. The reversal of 1321538416128 is 8216148351231.

1321538416128 is a `hidden beast` number, since 1 + 3 + 21 + 5 + 3 + 8 + 4 + 1 + 612 + 8 = 666.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (1321538416129) by changing a digit.

It is a polite number, since it can be written in 71 ways as a sum of consecutive naturals, for example, 836945643 + ... + 836947221.

It is an arithmetic number, because the mean of its divisors is an integer number (6491436952).

Almost surely, 2^{1321538416128} is an apocalyptic number.

1321538416128 is a gapful number since it is divisible by the number (18) 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 1321538416128, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (2336917302720).

1321538416128 is an abundant number, since it is smaller than the sum of its proper divisors (3352296189312).

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

1321538416128 is an frugal number, since it uses more digits than its factorization.

1321538416128 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1681 (or 1622 counting only the distinct ones).

The product of its digits is 276480, while the sum is 45.

The spelling of 1321538416128 in words is "one trillion, three hundred twenty-one billion, five hundred thirty-eight million, four hundred sixteen thousand, one hundred twenty-eight".