1212011100 has 108 divisors (see below), whose sum is σ = 3939763464. Its totient is φ = 323196480.

The previous prime is 1212011089. The next prime is 1212011111. The reversal of 1212011100 is 11102121.

It is a happy number.

It is an interprime number because it is at equal distance from previous prime (1212011089) and next prime (1212011111).

It is a tau number, because it is divible by the number of its divisors (108).

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 polite number, since it can be written in 35 ways as a sum of consecutive naturals, for example, 639 + ... + 49238.

Almost surely, 2^1212011100 is an apocalyptic number.

1212011100 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 1212011100, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (1969881732).

1212011100 is an abundant number, since it is smaller than the sum of its proper divisors (2727752364).

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

1212011100 is a wasteful number, since it uses less digits than its factorization.

1212011100 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 49906 (or 49887 counting only the distinct ones).

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

The square root of 1212011100 is about 34813.9497902780. The cubic root of 1212011100 is about 1066.1922771154.

Adding to 1212011100 its reverse (11102121), we get a palindrome (1223113221).

It can be divided in two parts, 12120 and 11100, that added together give a triangular number (23220 = T₂₁₅).

The spelling of 1212011100 in words is "one billion, two hundred twelve million, eleven thousand, one hundred".