21031113100 has 72 divisors (see below), whose sum is σ = 48435368688. Its totient is φ = 7899033600.

The previous prime is 21031113073. The next prime is 21031113107. The reversal of 21031113100 is 131113012.

It is a super-2 number, since 2×21031113100² (a number of 21 digits) contains 22 as substring.

It is not an unprimeable number, because it can be changed into a prime (21031113107) 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, 721815 + ... + 750385.

It is an arithmetic number, because the mean of its divisors is an integer number (672713454).

Almost surely, 2^21031113100 is an apocalyptic number.

21031113100 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 21031113100, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (24217684344).

21031113100 is an abundant number, since it is smaller than the sum of its proper divisors (27404255588).

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

21031113100 is a wasteful number, since it uses less digits than its factorization.

21031113100 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 29035 (or 29028 counting only the distinct ones).

The product of its (nonzero) digits is 18, while the sum is 13.

Adding to 21031113100 its reverse (131113012), we get a palindrome (21162226112).

The spelling of 21031113100 in words is "twenty-one billion, thirty-one million, one hundred thirteen thousand, one hundred".