1221131032320 has 144 divisors (see below), whose sum is σ = 3902030600832. Its totient is φ = 325464330240.

The previous prime is 1221131032267. The next prime is 1221131032493. The reversal of 1221131032320 is 232301311221.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 7332699 + ... + 7497381.

It is an arithmetic number, because the mean of its divisors is an integer number (27097434728).

Almost surely, 2^{1221131032320} is an apocalyptic number.

1221131032320 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 1221131032320, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (1951015300416).

1221131032320 is an abundant number, since it is smaller than the sum of its proper divisors (2680899568512).

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

1221131032320 is a wasteful number, since it uses less digits than its factorization.

1221131032320 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 166638 (or 166624 counting only the distinct ones).

The product of its (nonzero) digits is 432, while the sum is 21.

Adding to 1221131032320 its reverse (232301311221), we get a palindrome (1453432343541).

The spelling of 1221131032320 in words is "one trillion, two hundred twenty-one billion, one hundred thirty-one million, thirty-two thousand, three hundred twenty".