1321129555216 has 45 divisors (see below), whose sum is σ = 2719276354821. Its totient is φ = 621671245056.

The previous prime is 1321129555201. The next prime is 1321129555217. The reversal of 1321129555216 is 6125559211231.

The square root of 1321129555216 is 1149404.

It is a perfect power (a square), and thus also a powerful number.

It can be written as a sum of positive squares in only one way, i.e., 1028561072400 + 292568482816 = 1014180^2 + 540896^2 .

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (1321129555217) by changing a digit.

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 8 ways as a sum of consecutive naturals, for example, 78151021 + ... + 78167923.

Almost surely, 2^{1321129555216} is an apocalyptic number.

1321129555216 is a gapful number since it is divisible by the number (16) formed by its first and last digit.

1321129555216 is the 1149404-th square number.

It is an amenable number.

1321129555216 is an abundant number, since it is smaller than the sum of its proper divisors (1398146799605).

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

1321129555216 is an frugal number, since it uses more digits than its factorization.

1321129555216 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 33848 (or 16922 counting only the distinct ones).

The product of its digits is 162000, while the sum is 43.

The spelling of 1321129555216 in words is "one trillion, three hundred twenty-one billion, one hundred twenty-nine million, five hundred fifty-five thousand, two hundred sixteen".