1321779812000 has 192 divisors, whose sum is σ = 3361160668320. Its totient is φ = 510492672000.

The previous prime is 1321779811993. The next prime is 1321779812009. The reversal of 1321779812000 is 2189771231.

It is a happy number.

It can be written as a sum of positive squares in 16 ways, for example, as 754764787984 + 567015024016 = 868772^2 + 753004^2 .

It is a Harshad number since it is a multiple of its sum of digits (41).

It is not an unprimeable number, because it can be changed into a prime (1321779812009) by changing a digit.

It is a polite number, since it can be written in 31 ways as a sum of consecutive naturals, for example, 15866456 + ... + 15949544.

Almost surely, 2^{1321779812000} is an apocalyptic number.

1321779812000 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 1321779812000, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (1680580334160).

1321779812000 is an abundant number, since it is smaller than the sum of its proper divisors (2039380856320).

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

1321779812000 is an equidigital number, since it uses as much as digits as its factorization.

1321779812000 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 83252 (or 83234 counting only the distinct ones).

The product of its (nonzero) digits is 42336, while the sum is 41.

The spelling of 1321779812000 in words is "one trillion, three hundred twenty-one billion, seven hundred seventy-nine million, eight hundred twelve thousand".