1220121220 has 24 divisors (see below), whose sum is σ = 2566600344. Its totient is φ = 487220736.

The previous prime is 1220121169. The next prime is 1220121247. The reversal of 1220121220 is 221210221.

It is a happy number.

It can be written as a sum of positive squares in 4 ways, for example, as 281434176 + 938687044 = 16776^2 + 30638^2 .

It is a self number, because there is not a number n which added to its sum of digits gives 1220121220.

It is an unprimeable number.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 39579 + ... + 63298.

It is an arithmetic number, because the mean of its divisors is an integer number (106941681).

Almost surely, 2^1220121220 is an apocalyptic number.

1220121220 is a gapful number since it is divisible by the number (10) formed by its first and last digit.

It is an amenable number.

1220121220 is an abundant number, since it is smaller than the sum of its proper divisors (1346479124).

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

1220121220 is a wasteful number, since it uses less digits than its factorization.

1220121220 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 103479 (or 103477 counting only the distinct ones).

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

The square root of 1220121220 is about 34930.2336092961. The cubic root of 1220121220 is about 1068.5651189150.

Adding to 1220121220 its reverse (221210221), we get a palindrome (1441331441).

The spelling of 1220121220 in words is "one billion, two hundred twenty million, one hundred twenty-one thousand, two hundred twenty".