1212220100 has 108 divisors (see below), whose sum is σ = 3255666624. Its totient is φ = 383610240.

The previous prime is 1212220091. The next prime is 1212220111. The reversal of 1212220100 is 10222121.

It is a happy number.

It is an unprimeable number.

It is a polite number, since it can be written in 35 ways as a sum of consecutive naturals, for example, 113177 + ... + 123423.

Almost surely, 2^1212220100 is an apocalyptic number.

1212220100 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 1212220100, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (1627833312).

1212220100 is an abundant number, since it is smaller than the sum of its proper divisors (2043446524).

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

1212220100 is a wasteful number, since it uses less digits than its factorization.

1212220100 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 10294 (or 10274 counting only the distinct ones).

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

The square root of 1212220100 is about 34816.9513312122. The cubic root of 1212220100 is about 1066.2535585615.

Adding to 1212220100 its reverse (10222121), we get a palindrome (1222442221).

It can be divided in two parts, 121 and 2220100, that multiplied together give a square (268632100 = 16390²).

The spelling of 1212220100 in words is "one billion, two hundred twelve million, two hundred twenty thousand, one hundred".