21316122100 has 162 divisors, whose sum is σ = 58267712034. Its totient is φ = 6745939200.

The previous prime is 21316122089. The next prime is 21316122103. The reversal of 21316122100 is 122161312.

It can be written as a sum of positive squares in 9 ways, for example, as 11326919184 + 9989202916 = 106428^2 + 99946^2 .

It is a super-2 number, since 2×21316122100² (a number of 21 digits) contains 22 as substring.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21316122103) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (19) of ones.

It is a polite number, since it can be written in 53 ways as a sum of consecutive naturals, for example, 815230 + ... + 840970.

Almost surely, 2^21316122100 is an apocalyptic number.

21316122100 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 21316122100, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (29133856017).

21316122100 is an abundant number, since it is smaller than the sum of its proper divisors (36951589934).

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

21316122100 is a wasteful number, since it uses less digits than its factorization.

21316122100 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 25795 (or 25768 counting only the distinct ones).

The product of its (nonzero) digits is 144, while the sum is 19.

Adding to 21316122100 its reverse (122161312), we get a palindrome (21438283412).

The spelling of 21316122100 in words is "twenty-one billion, three hundred sixteen million, one hundred twenty-two thousand, one hundred".