21203900100 has 216 divisors, whose sum is σ = 69496801920. Its totient is φ = 5397258240.

The previous prime is 21203900089. The next prime is 21203900119. The reversal of 21203900100 is 100930212.

It is a happy number.

It is a Harshad number since it is a multiple of its sum of digits (18).

It is an unprimeable number.

It is a polite number, since it can be written in 71 ways as a sum of consecutive naturals, for example, 15048196 + ... + 15049604.

Almost surely, 2^21203900100 is an apocalyptic number.

21203900100 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 21203900100, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (34748400960).

21203900100 is an abundant number, since it is smaller than the sum of its proper divisors (48292901820).

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

21203900100 is a wasteful number, since it uses less digits than its factorization.

21203900100 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 2179 (or 2169 counting only the distinct ones).

The product of its (nonzero) digits is 108, while the sum is 18.

The spelling of 21203900100 in words is "twenty-one billion, two hundred three million, nine hundred thousand, one hundred".