1221220120 has 16 divisors (see below), whose sum is σ = 2747745360. Its totient is φ = 488488032.

The previous prime is 1221220111. The next prime is 1221220123. The reversal of 1221220120 is 210221221.

It is a happy number.

It is a self number, because there is not a number n which added to its sum of digits gives 1221220120.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (1221220123) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 15265212 + ... + 15265291.

It is an arithmetic number, because the mean of its divisors is an integer number (171734085).

Almost surely, 2^1221220120 is an apocalyptic number.

1221220120 is a gapful number since it is divisible by the number (10) formed by its first and last digit.

It is an amenable number.

1221220120 is an abundant number, since it is smaller than the sum of its proper divisors (1526525240).

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

1221220120 is a wasteful number, since it uses less digits than its factorization.

1221220120 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 30530514 (or 30530510 counting only the distinct ones).

The product of its (nonzero) digits is 32, while the sum is 13.

The square root of 1221220120 is about 34945.9599953986. The cubic root of 1221220120 is about 1068.8858230764.

Adding to 1221220120 its reverse (210221221), we get a palindrome (1431441341).

The spelling of 1221220120 in words is "one billion, two hundred twenty-one million, two hundred twenty thousand, one hundred twenty".