21112110100 has 72 divisors (see below), whose sum is σ = 47269474560. Its totient is φ = 8180465280.

The previous prime is 21112110037. The next prime is 21112110109. The reversal of 21112110100 is 101121112.

It is a Harshad number since it is a multiple of its sum of digits (10).

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21112110109) by changing a digit.

It is a polite number, since it can be written in 23 ways as a sum of consecutive naturals, for example, 393489 + ... + 443911.

It is an arithmetic number, because the mean of its divisors is an integer number (656520480).

Almost surely, 2^21112110100 is an apocalyptic number.

21112110100 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 21112110100, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (23634737280).

21112110100 is an abundant number, since it is smaller than the sum of its proper divisors (26157364460).

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

21112110100 is a wasteful number, since it uses less digits than its factorization.

21112110100 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 50569 (or 50562 counting only the distinct ones).

The product of its (nonzero) digits is 4, while the sum is 10.

Adding to 21112110100 its reverse (101121112), we get a palindrome (21213231212).

The spelling of 21112110100 in words is "twenty-one billion, one hundred twelve million, one hundred ten thousand, one hundred".