1213112121100 has 144 divisors (see below), whose sum is σ = 2906668398816. Its totient is φ = 435790080000.

The previous prime is 1213112121097. The next prime is 1213112121107. The reversal of 1213112121100 is 11212113121.

It is a happy number.

It is not an unprimeable number, because it can be changed into a prime (1213112121107) by changing a digit.

It is a polite number, since it can be written in 47 ways as a sum of consecutive naturals, for example, 50760754 + ... + 50784646.

It is an arithmetic number, because the mean of its divisors is an integer number (20185197214).

Almost surely, 2^{1213112121100} is an apocalyptic number.

1213112121100 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 1213112121100, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (1453334199408).

1213112121100 is an abundant number, since it is smaller than the sum of its proper divisors (1693556277716).

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

1213112121100 is a wasteful number, since it uses less digits than its factorization.

1213112121100 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 24476 (or 24469 counting only the distinct ones).

The product of its (nonzero) digits is 24, while the sum is 16.

Adding to 1213112121100 its reverse (11212113121), we get a palindrome (1224324234221).

The spelling of 1213112121100 in words is "one trillion, two hundred thirteen billion, one hundred twelve million, one hundred twenty-one thousand, one hundred".