21030021100 has 36 divisors (see below), whose sum is σ = 49783798008. Its totient is φ = 7647280000.

The previous prime is 21030021041. The next prime is 21030021127. The reversal of 21030021100 is 112003012.

It is a Harshad number since it is a multiple of its sum of digits (10).

It is an unprimeable number.

It is a polite number, since it can be written in 11 ways as a sum of consecutive naturals, for example, 9558001 + ... + 9560200.

It is an arithmetic number, because the mean of its divisors is an integer number (1382883278).

Almost surely, 2^21030021100 is an apocalyptic number.

21030021100 is a gapful number since it is divisible by the number (20) formed by its first and last digit.

It is an amenable number.

21030021100 is an abundant number, since it is smaller than the sum of its proper divisors (28753776908).

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

21030021100 is a wasteful number, since it uses less digits than its factorization.

21030021100 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 19118226 (or 19118219 counting only the distinct ones).

The product of its (nonzero) digits is 12, while the sum is 10.

Adding to 21030021100 its reverse (112003012), we get a palindrome (21142024112).

The spelling of 21030021100 in words is "twenty-one billion, thirty million, twenty-one thousand, one hundred".