21031300100 has 72 divisors (see below), whose sum is σ = 48750582888. Its totient is φ = 7847526400.

The previous prime is 21031300091. The next prime is 21031300109. The reversal of 21031300100 is 100313012.

It is an interprime number because it is at equal distance from previous prime (21031300091) and next prime (21031300109).

It can be written as a sum of positive squares in 12 ways, for example, as 13108876036 + 7922424064 = 114494^2 + 89008^2 .

It is not an unprimeable number, because it can be changed into a prime (21031300109) 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, 137360 + ... + 246840.

It is an arithmetic number, because the mean of its divisors is an integer number (677091429).

Almost surely, 2^21031300100 is an apocalyptic number.

21031300100 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 21031300100, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (24375291444).

21031300100 is an abundant number, since it is smaller than the sum of its proper divisors (27719282788).

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

21031300100 is a wasteful number, since it uses less digits than its factorization.

21031300100 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 109625 (or 109618 counting only the distinct ones).

The product of its (nonzero) digits is 18, while the sum is 11.

Adding to 21031300100 its reverse (100313012), we get a palindrome (21131613112).

The spelling of 21031300100 in words is "twenty-one billion, thirty-one million, three hundred thousand, one hundred".