21100112010 has 80 divisors (see below), whose sum is σ = 57116961000. Its totient is φ = 5588901504.

The previous prime is 21100111999. The next prime is 21100112017. The reversal of 21100112010 is 1021100112.

It is a happy number.

It can be written as a sum of positive squares in 4 ways, for example, as 15001595361 + 6098516649 = 122481^2 + 78093^2 .

It is a Harshad number since it is a multiple of its sum of digits (9).

It is a junction number, because it is equal to n+sod(n) for n = 21100111983 and 21100112001.

It is not an unprimeable number, because it can be changed into a prime (21100112017) by changing a digit.

It is a polite number, since it can be written in 39 ways as a sum of consecutive naturals, for example, 33276 + ... + 208104.

Almost surely, 2^21100112010 is an apocalyptic number.

It is a practical number, because each smaller number is the sum of distinct divisors of 21100112010, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (28558480500).

21100112010 is an abundant number, since it is smaller than the sum of its proper divisors (36016848990).

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

21100112010 is a wasteful number, since it uses less digits than its factorization.

21100112010 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 174997 (or 174988 counting only the distinct ones).

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

Adding to 21100112010 its reverse (1021100112), we get a palindrome (22121212122).

The spelling of 21100112010 in words is "twenty-one billion, one hundred million, one hundred twelve thousand, ten".