1212020100 has 216 divisors, whose sum is σ = 4133126088. Its totient is φ = 295833600.

The previous prime is 1212020093. The next prime is 1212020123. The reversal of 1212020100 is 10202121.

It can be written as a sum of positive squares in 12 ways, for example, as 18870336 + 1193149764 = 4344^2 + 34542^2 .

It is a Harshad number since it is a multiple of its sum of digits (9).

It is an unprimeable number.

It is a polite number, since it can be written in 71 ways as a sum of consecutive naturals, for example, 565030 + ... + 567170.

It is an arithmetic number, because the mean of its divisors is an integer number (19134843).

Almost surely, 2^1212020100 is an apocalyptic number.

1212020100 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 1212020100, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (2066563044).

1212020100 is an abundant number, since it is smaller than the sum of its proper divisors (2921105988).

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

1212020100 is a wasteful number, since it uses less digits than its factorization.

1212020100 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 2215 (or 2205 counting only the distinct ones).

The product of its (nonzero) digits is 8, while the sum is 9.

The square root of 1212020100 is about 34814.0790485688. The cubic root of 1212020100 is about 1066.1949161745.

Adding to 1212020100 its reverse (10202121), we get a palindrome (1222222221).

The spelling of 1212020100 in words is "one billion, two hundred twelve million, twenty thousand, one hundred".