1221322120 has 128 divisors (see below), whose sum is σ = 2911645440. Its totient is φ = 460615680.

The previous prime is 1221322117. The next prime is 1221322127. The reversal of 1221322120 is 212231221.

It is a happy number.

It is a junction number, because it is equal to n+sod(n) for n = 1221322094 and 1221322103.

It is not an unprimeable number, because it can be changed into a prime (1221322127) 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, 8914692 + ... + 8914828.

It is an arithmetic number, because the mean of its divisors is an integer number (22747230).

Almost surely, 2^1221322120 is an apocalyptic number.

1221322120 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 1221322120, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (1455822720).

1221322120 is an abundant number, since it is smaller than the sum of its proper divisors (1690323320).

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

1221322120 is a wasteful number, since it uses less digits than its factorization.

1221322120 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 335 (or 331 counting only the distinct ones).

The product of its (nonzero) digits is 96, while the sum is 16.

The square root of 1221322120 is about 34947.4193610916. The cubic root of 1221322120 is about 1068.9155811074.

Adding to 1221322120 its reverse (212231221), we get a palindrome (1433553341).

The spelling of 1221322120 in words is "one billion, two hundred twenty-one million, three hundred twenty-two thousand, one hundred twenty".