1281121380000 has 1440 divisors, whose sum is σ = 5867611263360. Its totient is φ = 266112000000.

The previous prime is 1281121379981. The next prime is 1281121380023. The reversal of 1281121380000 is 831211821.

1281121380000 is a `hidden beast` number, since 1 + 281 + 1 + 2 + 1 + 380 + 0 + 0 + 0 = 666.

It is a tau number, because it is divible by the number of its divisors (1440).

It is a Harshad number since it is a multiple of its sum of digits (27).

It is an unprimeable number.

It is a polite number, since it can be written in 239 ways as a sum of consecutive naturals, for example, 457378600 + ... + 457381400.

It is an arithmetic number, because the mean of its divisors is an integer number (4074730044).

Almost surely, 2^{1281121380000} is an apocalyptic number.

1281121380000 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 1281121380000, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (2933805631680).

1281121380000 is an abundant number, since it is smaller than the sum of its proper divisors (4586489883360).

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

1281121380000 is a wasteful number, since it uses less digits than its factorization.

1281121380000 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 2869 (or 2829 counting only the distinct ones).

The product of its (nonzero) digits is 768, while the sum is 27.

Adding to 1281121380000 its reverse (831211821), we get a palindrome (1281952591821).

The spelling of 1281121380000 in words is "one trillion, two hundred eighty-one billion, one hundred twenty-one million, three hundred eighty thousand".