1321200000000 has 594 divisors, whose sum is σ = 4781661614288. Its totient is φ = 351360000000.

The previous prime is 1321199999989. The next prime is 1321200000013. The reversal of 1321200000000 is 21231.

It is a happy number.

It is a Harshad number since it is a multiple of its sum of digits (9).

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 53 ways as a sum of consecutive naturals, for example, 3599999817 + ... + 3600000183.

Almost surely, 2^{1321200000000} is an apocalyptic number.

1321200000000 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 1321200000000, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (2390830807144).

1321200000000 is an abundant number, since it is smaller than the sum of its proper divisors (3460461614288).

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

1321200000000 is an frugal number, since it uses more digits than its factorization.

1321200000000 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 433 (or 377 counting only the distinct ones).

The product of its (nonzero) digits is 12, while the sum is 9.

Adding to 1321200000000 its reverse (21231), we get a palindrome (1321200021231).

The spelling of 1321200000000 in words is "one trillion, three hundred twenty-one billion, two hundred million", and thus it is an aban number.