1221311310120 has 384 divisors, whose sum is σ = 4355934485760. Its totient is φ = 294314618880.

The previous prime is 1221311310113. The next prime is 1221311310137. The reversal of 1221311310120 is 210131131221.

1221311310120 is a `hidden beast` number, since 1 + 2 + 21 + 311 + 310 + 1 + 20 = 666.

It is a super-3 number, since 3×1221311310120³ (a number of 37 digits) contains 333 as substring.

It is a Harshad number since it is a multiple of its sum of digits (18).

It is a junction number, because it is equal to n+sod(n) for n = 1221311310093 and 1221311310102.

It is an unprimeable number.

It is a polite number, since it can be written in 95 ways as a sum of consecutive naturals, for example, 638426284 + ... + 638428196.

It is an arithmetic number, because the mean of its divisors is an integer number (11343579390).

Almost surely, 2^{1221311310120} is an apocalyptic number.

1221311310120 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 1221311310120, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (2177967242880).

1221311310120 is an abundant number, since it is smaller than the sum of its proper divisors (3134623175640).

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

1221311310120 is a wasteful number, since it uses less digits than its factorization.

1221311310120 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 2817 (or 2810 counting only the distinct ones).

The product of its (nonzero) digits is 72, while the sum is 18.

Adding to 1221311310120 its reverse (210131131221), we get a palindrome (1431442441341).

The spelling of 1221311310120 in words is "one trillion, two hundred twenty-one billion, three hundred eleven million, three hundred ten thousand, one hundred twenty".