1221020120 has 16 divisors (see below), whose sum is σ = 2747295360. Its totient is φ = 488408032.

The previous prime is 1221020117. The next prime is 1221020137. The reversal of 1221020120 is 210201221.

It is a happy number.

1221020120 is digitally balanced in base 6, because in such base it contains all the possibile digits an equal number of times.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 15262712 + ... + 15262791.

It is an arithmetic number, because the mean of its divisors is an integer number (171705960).

Almost surely, 2^1221020120 is an apocalyptic number.

1221020120 is a gapful number since it is divisible by the number (10) formed by its first and last digit.

It is an amenable number.

1221020120 is an abundant number, since it is smaller than the sum of its proper divisors (1526275240).

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

1221020120 is a wasteful number, since it uses less digits than its factorization.

1221020120 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 30525514 (or 30525510 counting only the distinct ones).

The product of its (nonzero) digits is 16, while the sum is 11.

The square root of 1221020120 is about 34943.0983171212. The cubic root of 1221020120 is about 1068.8274691858.

Adding to 1221020120 its reverse (210201221), we get a palindrome (1431221341).

The spelling of 1221020120 in words is "one billion, two hundred twenty-one million, twenty thousand, one hundred twenty".