1211210100 has 216 divisors, whose sum is σ = 4027936640. Its totient is φ = 303575040.

The previous prime is 1211210089. The next prime is 1211210129. The reversal of 1211210100 is 10121121.

It is a happy number.

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

It is a congruent number.

It is an unprimeable number.

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 71 ways as a sum of consecutive naturals, for example, 3300117 + ... + 3300483.

Almost surely, 2^1211210100 is an apocalyptic number.

1211210100 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 1211210100, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (2013968320).

1211210100 is an abundant number, since it is smaller than the sum of its proper divisors (2816726540).

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

1211210100 is a wasteful number, since it uses less digits than its factorization.

1211210100 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 599 (or 589 counting only the distinct ones).

The product of its (nonzero) digits is 4, while the sum is 9.

The square root of 1211210100 is about 34802.4438797048. The cubic root of 1211210100 is about 1065.9573485136.

Adding to 1211210100 its reverse (10121121), we get a palindrome (1221331221).

The spelling of 1211210100 in words is "one billion, two hundred eleven million, two hundred ten thousand, one hundred".