1321520811912 has 480 divisors, whose sum is σ = 4368718431000. Its totient is φ = 372095410176.

The previous prime is 1321520811907. The next prime is 1321520811931. The reversal of 1321520811912 is 2191180251231.

1321520811912 is a `hidden beast` number, since 1 + 3 + 2 + 1 + 520 + 8 + 119 + 12 = 666.

It can be written as a sum of positive squares in 4 ways, for example, as 800083736676 + 521437075236 = 894474^2 + 722106^2 .

It is a Harshad number since it is a multiple of its sum of digits (36).

It is an unprimeable number.

It is a polite number, since it can be written in 119 ways as a sum of consecutive naturals, for example, 853143714 + ... + 853145262.

Almost surely, 2^{1321520811912} is an apocalyptic number.

1321520811912 is a gapful number since it is divisible by the number (12) 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 1321520811912, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (2184359215500).

1321520811912 is an abundant number, since it is smaller than the sum of its proper divisors (3047197619088).

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

1321520811912 is a wasteful number, since it uses less digits than its factorization.

1321520811912 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1955 (or 1935 counting only the distinct ones).

The product of its (nonzero) digits is 8640, while the sum is 36.

The spelling of 1321520811912 in words is "one trillion, three hundred twenty-one billion, five hundred twenty million, eight hundred eleven thousand, nine hundred twelve".