21002031100 has 18 divisors (see below), whose sum is σ = 45574407704. Its totient is φ = 8400812400.

The previous prime is 21002031067. The next prime is 21002031103. The reversal of 21002031100 is 113020012.

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

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21002031103) by changing a digit.

It is a polite number, since it can be written in 5 ways as a sum of consecutive naturals, for example, 105010056 + ... + 105010255.

Almost surely, 2^21002031100 is an apocalyptic number.

21002031100 is a gapful number since it is divisible by the number (20) formed by its first and last digit.

It is an amenable number.

21002031100 is an abundant number, since it is smaller than the sum of its proper divisors (24572376604).

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

21002031100 is a wasteful number, since it uses less digits than its factorization.

21002031100 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 210020325 (or 210020318 counting only the distinct ones).

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

Adding to 21002031100 its reverse (113020012), we get a palindrome (21115051112).

The spelling of 21002031100 in words is "twenty-one billion, two million, thirty-one thousand, one hundred".