20121123100 has 216 divisors, whose sum is σ = 49235286240. Its totient is φ = 7128576000.

The previous prime is 20121123091. The next prime is 20121123179. The reversal of 20121123100 is 132112102.

It is a super-2 number, since 2×20121123100² (a number of 21 digits) contains 22 as substring.

It is a Harshad number since it is a multiple of its sum of digits (13).

It is a congruent number.

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, 49195696 + ... + 49196104.

It is an arithmetic number, because the mean of its divisors is an integer number (227941140).

Almost surely, 2^20121123100 is an apocalyptic number.

20121123100 is a gapful number since it is divisible by the number (20) 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 20121123100, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (24617643120).

20121123100 is an abundant number, since it is smaller than the sum of its proper divisors (29114163140).

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

20121123100 is a wasteful number, since it uses less digits than its factorization.

20121123100 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 561 (or 541 counting only the distinct ones).

The product of its (nonzero) digits is 24, while the sum is 13.

Adding to 20121123100 its reverse (132112102), we get a palindrome (20253235202).

The spelling of 20121123100 in words is "twenty billion, one hundred twenty-one million, one hundred twenty-three thousand, one hundred".