21002210100 has 216 divisors, whose sum is σ = 67915936088. Its totient is φ = 5424537600.

The previous prime is 21002210093. The next prime is 21002210111. The reversal of 21002210100 is 101220012.

It can be written as a sum of positive squares in 12 ways, for example, as 405941904 + 20596268196 = 20148^2 + 143514^2 .

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

It is a congruent number.

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written in 71 ways as a sum of consecutive naturals, for example, 8023992 + ... + 8026608.

Almost surely, 2^21002210100 is an apocalyptic number.

21002210100 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 21002210100, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (33957968044).

21002210100 is an abundant number, since it is smaller than the sum of its proper divisors (46913725988).

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

21002210100 is a wasteful number, since it uses less digits than its factorization.

21002210100 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 2915 (or 2905 counting only the distinct ones).

The product of its (nonzero) digits is 8, while the sum is 9.

Adding to 21002210100 its reverse (101220012), we get a palindrome (21103430112).

The spelling of 21002210100 in words is "twenty-one billion, two million, two hundred ten thousand, one hundred".