21100120000 has 140 divisors (see below), whose sum is σ = 52918248240. Its totient is φ = 8343808000.

The previous prime is 21100119991. The next prime is 21100120001. The reversal of 21100120000 is 2100112.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21100120001) by changing a digit.

It is a polite number, since it can be written in 19 ways as a sum of consecutive naturals, for example, 3557037 + ... + 3562963.

Almost surely, 2^21100120000 is an apocalyptic number.

21100120000 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 21100120000, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (26459124120).

21100120000 is an abundant number, since it is smaller than the sum of its proper divisors (31818128240).

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

21100120000 is an frugal number, since it uses more digits than its factorization.

21100120000 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 6048 (or 6023 counting only the distinct ones).

The product of its (nonzero) digits is 4, while the sum is 7.

Adding to 21100120000 its reverse (2100112), we get a palindrome (21102220112).

The spelling of 21100120000 in words is "twenty-one billion, one hundred million, one hundred twenty thousand".